Acidic Isoforms Research Articles

Sodium Tetraborate Induces Systemic Resistance in Watermelon against Stagonosporopsis cucurbitacearum

Imbibing watermelon seeds in 1 mM sodium tetraborate (Na2B4O7) for 24 h systemically protected plants against foliar infection by Stagonosporopsis cucurbitacearum in detached leaves and under greenhouse conditions. The treatment resulted in both a reduction in the overall percentage of leaf infection as well as in the size of lesions. Studies of the mechanisms by which Na2B4O7 protected watermelon showed that there was no direct effect on the S. cucurbitacearum mycelium growth in vitro. On the other hand, plants raised from seeds primed with Na2B4O7 showed a higher frequency of fluorescent epidermal cells compared to the plants treated with water. This indicates that a higher number of cells expressed the hypersensitive response after Na2B4O7 priming. In addition, there was an increase in peroxidase activity and an enhanced accumulation of a 45 kDa acidic peroxidase isoform during the early stages of infection in plants treated with Na2B4O7 compared to plants treated with water and this was positively correlated to the reduction of leaf infection caused by the pathogen. These results indicate that Na2B4O7 is able to induce systemic resistance in watermelon against S. cucurbitacearum by activating the hypersensitive reaction at penetration sites, increasing peroxidase activity and altering the peroxidase isozyme profile. Although each individual response may only have had a minor effect, their combined effects had a reducing effect on the disease.

Abstract P1172: Shear-mediated Remodeling Of Platelet Surface Glycosylation: How Can Platelets Trim Their Sugar Coats?

Mechanical circulatory support (MCS) is associated with bleeding complications often requiring multiple transfusions or reoperation. Hypershear stress within device-supported circulation promotes platelet dysfunction associated with pro-apoptosis, impaired aggregation, and microvesiculation - all contributors to bleeding. Recent studies showed that glycosylation of surface receptors, i.e. “ sugar coat ,” plays a major role in the regulation of platelet function and lifespan. We tested the hypothesis that shear stress promotes platelet surface deglycosylation by increasing platelet glycosidase activity. Methods: Human platelets were obtained from ACD-anticoagulated blood via gel filtration on Sepharose 2B. Platelets were exposed to neuraminidase and continuous shear stress in a hemodynamic shearing device. Platelets were stained with fluorophore-conjugated lectins binding terminal sialic acids (SNA I, MAL II) and galactose (ECA), anti-CD41 and anti-CD42a a/b. Multi-colored flow cytometry was used to quantify platelet surface glycosylation. Neuraminidase and galactosidase activities of intact and lysed platelets were measured using enzyme-specific fluorogenic substrates. Results: Exposure to shear stress and neuraminidase induced a significant decrease in platelet 2,6-sialylation and galactosylation, while 2,3-sialylation remained unaltered. Neuraminidase reinforced shear-mediated platelet desialylation, causing a prominent decrease in SNA binding even at low shear, and increased platelet galactose levels by unmasking the galactose residues capped by sialic acids. Shear stress resulted in a 9.5-fold increase in platelet neuraminidase and a 1.4-fold increase in galactosidase activities vs their basal levels. Neutral neuraminidase and galactosidase were upregulated by shear, while acidic isoforms did not increase, suggesting that other than lysosomal glycosidase pools are involved. Shear stress promotes platelet deglycosylation via upregulation of platelet neuraminidase and galactosidase activities. Developing therapeutic strategies for the preservation of platelet glycosylation offers significant translational potential for the pharmacologic management of MCS platelet dysfunction and bleeding.

Structural and Functional Analysis of CEX Fractions Collected from a Novel Avastin® Biosimilar Candidate and Its Innovator: A Comparative Study.

Avastin® is a humanized recombinant monoclonal antibody used to treat cancer by targeting VEGF-A to inhibit angiogenesis. SIMAB054, an Avastin® biosimilar candidate developed in this study, showed a different charge variant profile than its innovator. Thus, it is fractionated into acidic, main, and basic isoforms and collected physically by Cation Exchange Chromatography (CEX) for a comprehensive structural and functional analysis. The innovator product, fractionated into the same species and collected by the same method, is used as a reference for comparative analysis. Ultra-Performance Liquid Chromatography (UPLC) ESI-QToF was used to analyze the modifications leading to charge heterogeneities at intact protein and peptide levels. The C-terminal lysine clipping and glycosylation profiles of the samples were monitored by intact mAb analysis. The post-translational modifications, including oxidation, deamidation, and N-terminal pyroglutamic acid formation, were determined by peptide mapping analysis in the selected signal peptides. The relative binding affinities of the fractionated charge isoforms against the antigen, VEGF-A, and the neonatal receptor, FcRn, were revealed by Surface Plasmon Resonance (SPR) studies. The results show that all CEX fractions from the innovator product and the SIMAB054 shared the same structural variants, albeit in different ratios. Common glycoforms and post-translational modifications were the same, but at different percentages for some samples. The dissimilarities were mostly originating from the presence of extra C-term Lysin residues, which are prone to enzymatic degradation in the body, and thus they were previously assessed as clinically irrelevant. Another critical finding was the presence of different glyco proteoforms in different charge species, such as increased galactosylation in the acidic and afucosylation in the basic species. SPR characterization of the isolated charge variants further confirmed that basic species found in the CEX analyses of the biosimilar candidate were also present in the innovator product, although at lower amounts. The charge variants’ in vitro antigen- and neonatal receptor-binding activities varied amongst the samples, which could be further investigated in vivo with a larger sample set to reveal the impact on the pharmacokinetics of drug candidates. Minor structural differences may explain antigen-binding differences in the isolated charge variants, which is a key parameter in a comparability exercise. Consequently, such a biosimilar candidate may not comply with high regulatory standards unless the binding differences observed are justified and demonstrated not to have any clinical impact.

O-279 The type of gonadotrophin: Does it improve ART outcome?

Abstract Ovarian stimulation is a vital clinical component of an IVF cycle, with gonadotrophins being the main stimulation drugs. Follicle stimulating hormone (FSH), the key driver of follicle recruitment during an ovarian cycle is a complex glycosylated protein comprised of an α and β subunit with four glycosylation sites. Differences in glycosylation lead to heterogeneity with the FSH isoforms varying in their receptor binding and biological activity. The cyclic physiological variation of FSH isoforms and the FSH threshold/ window concept lead to the selection of a single dominant follicle during a menstrual cycle. Surpassing the FSH threshold and extension of the FSH window with ovarian stimulation using gonadotrophins salvages follicles with higher FSH sensitivity leading to multi-follicular development and retrieval of multiple oocytes. The first IVF birth in 1978 was from a natural cycle and was preceded by several unsuccessful attempts at oocyte retrieval. Ovarian stimulation was therefore incorporated into IVF treatment to overcome the inefficiencies encountered with a natural cycle. The objective of ovarian stimulation during IVF treatment is to obtain several mature oocytes, leading to good quality embryos for immediate replacement and cryopreservation for future use. An ideal stimulation wherein gonadotrophins are the mainstay is one that achieves maximal efficacy, safety and cost-effectiveness. Several gonadotrophin preparations have been available for clinical use over the years since the first use of pregnant mare serum gonadotrophin (PMSG) in 1940 and the first successful birth using human pituitary gonadotrophin (hPG) in 1961. These initial preparations were soon abandoned due to concerns with antigenicity and safety. Subsequent important milestones in the development gonadotrophins for clinical use include the urinary derived products, recombinant FSH preparations, long acting FSH and the biosimilars. Given the selection of gonadotrophins currently available, the apparent question is if they differ? Circulating FSH isoforms change during different stages of the menstrual cycle and through the reproductive stages. More acidic isoforms are predominant during the early follicular phase, with less acidic or basic isoforms predominant in the late follicular phase of the menstrual cycle, and more acidic isoforms during the menopausal stage. Similarly, the different FSH products vary in their properties owing to differences in their production and purification. Urinary derived products are more acidic compared to recombinant preparations and the different recombinant products vary in degree of acidity due to differences in the extent and pattern of glycosylation. The acidic and basic properties of gonadotrophin types influence metabolic stability, half-life and their biological activity. The question then remains if these differences in bioactivity affect clinical outcomes? Clinical effectiveness of the various gonadotrophins types should be addressed in the context of the different pituitary suppression regimens, ovarian response categories and patient variables given the implementation of individualised stimulation protocols. It is also imperative to clearly define successful clinical outcomes incorporating both efficacy and safety. Cumulative live birth rate (CLBR) following fresh and frozen embryo transfers resulting from one episode of ovarian stimulation should be adopted as the measure of the overall efficiency along with OHSS as a measure of immediate safety. There are several studies and systematic reviews comparing the different gonadotrophin types and products for various outcomes including surrogate endpoints, with inconsistent results attributed to differences in the inclusion/ exclusion criteria, heterogeneity across studies and varied quality of the primary studies. Furthermore, there have been sparse studies reporting on CLBR and there is a continuing debate on what would be considered as a relevant clinical difference in efficacy. In addition to efficacy and safety, the ultimate choice of gonadotrophin should be based on regional availability, patient acceptability and cost-effectiveness for a live birth.

A search for predictive biomarkers of ovine pre-partum vaginal prolapse

Ovine pre-partum vaginal prolapse (known as bearings in sheep) occurs within a few weeks prior to lambing and unless treated both ewes and unborn lambs will die. It is a worldwide problem with no clear aetiology. Rates of prolapse in New Zealand typically vary from 0.1 to 2% per annum, varying between seasons and farms. In order to determine preclinical changes leading to prolapse, blood samples were collected prior to prolapse occurring and analysed for changes in both protein and specific hormone and vitamin levels. 650 ewes were ear tagged and blood samples were taken one month prior to the beginning of lambing; 28 of these ewes subsequently prolapsed. Using an improved proteomic method plasma samples were subjected to 2D DIGE (two dimensional differential in gel electrophoresis) to determine if there were differences between the pre-prolapse and non-prolapsing ewes. Acidic isoforms of haptoglobin, a major acute phase protein in ruminants, increased approximately 3-fold in ewes prior to prolapse occurring. Total haptoglobin quantitation was confirmed with an independent assay. Although another plasma protein, α-1B-glycoprotein, was down regulated close to prolapse, the biological significance of this is unknown. While vitamin D levels were not associated with subsequent prolapse there was, however, a negative correlation between cortisol and days to prolapse from sampling (r2 = 0.36); i.e. ewes sampled closest to prolapse had higher plasma cortisol concentrations than controls. This raises the possibility that the ewes which prolapsed may have been suffering from chronic stress. Further research is needed.

GLYCOSYLATION FEATURES OF FOLLITROPIN DELTA (REKOVELLE®) MORE RESEMBLE THOSE OF NATURAL HUMAN FSH COMPARED TO FOLLITROPIN ALFA (GONAL F®).

Compare the glycosylation properties of follitropin delta, from a human cell line, with those of natural human derived FSH and with follitropin alfa from a hamster cell line. Follitropin delta (Rekovelle®) produced in PER.C6® human derived cell line, follitropin alfa (Gonal f®) produced in CHO derived cell line and natural human urinary derived FSH (Bravelle®) were used in the study. Isoelectric Focusing (IEF), was used to resolve and profile the isoforms present in FSH preparations. IEF was carried out using a gel with a pH range between pH 3-7. Glycans were released from FSH preparations by enzymatic digestion with PNGase and derivatized with 2-aminobenzamide (2AB). Glycans were sequenced with specific exoglycosidases and analysed using normal phase HPLC and weak anion exchange chromatography. A more acidic isoform profile was obtained by IEF for follitropin delta and human derived FSH in comparison to follitropin alfa. Compared to follitropin alfa, the released glycans from follitropin delta and natural human FSH both show higher abundance of tri- and tetra-antennary forms and a lower abundance of the di-antennary forms. Sialylation of glycans on follitropin delta and natural human FSH comprises both α2,3 linked and α2,6 linked sialic acid, whereas follitropin alfa exhibits only the α2,3 linked form. The resemblance of follitropin delta glycans to the human derived FSH was further supported by the presence of N-acetylgalactosamine (GalNAc) and bisecting N-acetylglucosamine (GlcNAc) which are absent in CHO-derived FSH (Table). Follitropin delta glycosylation is richer and more complex compared to follitropin alfa with a higher proportion of tri- and tetra-antennary and charged glycans, as well as by the presence of α2,6-linked sialic acid, GalNAc residues and bisecting GlcNAc. In these ways follitropin delta shares numerous glycosylation features and more resembles natural human derived FSH.

Synergism of in vitro plasmodicidal activity of phospholipase A2 isoforms isolated from panamanian Bothrops asper venom

Bothrops asper is one of the most important snake species in Central America, mainly because of its medical importance in countries like Ecuador, Panama and Costa Rica, where this species causes a high number of snakebite accidents. Several basic phospholipases A2 (PLA2s) have been previously characterized from B. asper venom, but few studies have been carried out with its acidic isoforms. In addition, since snake venom is a rich source of bioactive substances, it is necessary to investigate the biotechnological potential of its components. In this context, this study aimed to carry out the biochemical characterization of PLA2 isoforms isolated from B. asper venom and to evaluate the antiparasitic potential of these toxins. The venom and key fractions were subjected to different chromatographic steps, obtaining nine PLA2s, four acidic ones (BaspAc-I, BaspAc-II, BaspAc-III and BaspAc-IV) and five basic ones (BaspB-I, BaspB-II, BaspB-III, BaspB-IV and BaspB-V). The isoelectric points of the acidic PLA2s were also determined, which presented values ranging between 4.5 and 5. The findings indicated the isolation of five unpublished isoforms, four Asp49-PLA, corresponding to the group of acidic isoforms, and one Lys49-PLA2-like. Acidic PLA2s catalyzed the degradation of all substrates evaluated; however, for the basic PLA2s, there was a preference for phosphatidylglycerol and phosphatidic acid. The antiparasitic potential of the toxins was evaluated, and the acidic PLA2s demonstrated action against the epimastigote forms of T. cruzi and promastigote forms of L. infantum, while the basic PLA2s BaspB-II and BaspB-IV showed activity against P. falciparum. The results indicated an increase of up to 10 times in antiplasmodial activity, when the Asp49-PLA2 and Lys49-PLA2 were associated with one another, denoting synergistic action between these PLA2 isoforms. These findings correspond to the first report of synergistic antiplasmodial action for svPLA2s, demonstrating that these molecules may be important targets in the search for new antiparasitic agents.

Protease Inhibitors Purified from the Canola Meal Extracts of Two Genetically Diverse Genotypes Exhibit Antidiabetic and Antihypertension Properties

Valorization of vegetable oil waste residues is gaining importance due to their high protein and polyphenol contents. Protease inhibitors (PIs), proteins from these abundantly available waste residues, have recently gained importance in treating chronic diseases. This research aimed to use canola meal of genetically diverse Brassica napus genotypes, BLN-3347 and Rivette, to identify PIs with diverse functionalities in therapeutic and pharmacological applications. The canola meal PI purification steps involved: native PAGE and trypsin inhibition activity, followed by ammonium sulfate fractionation, anion exchange, gel filtration, and reverse-phase chromatography. The purified PI preparations were characterized using SDS-PAGE, isoelectric focusing (IEF), and N terminal sequencing. SDS-PAGE analysis of PI preparations under native reducing and nonreducing conditions revealed three polymorphic PIs in each genotype. The corresponding IEF of the genotype BLN-3347, exhibited three acidic isoforms with isoelectric points (pI) of 4.6, 4.0, and 3.9, while Rivette possessed three isoforms, exhibiting two basic forms of pI 8.65 and 9.9, and one acidic of pI 6.55. Purified PI preparations from both the genotypes displayed dipeptidyl peptidase-IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibition activities; the BLN-3347 PI preparation exhibited a strong inhibitory effect with lower IC50 values (DPP-IV 37.42 µg/mL; ACE 129 µg/mL) than that from Rivette (DPP-IV 67.97 µg/mL; ACE 376.2 µg/mL). In addition to potential human therapy, these highly polymorphic PIs, which can inhibit damaging serine proteases secreted by canola plant pathogens, have the potential to be used by canola plant breeders to seek qualitative trait locus (QTLs) linked to genes conferring resistance to canola diseases.

Transcriptional and proteomic insights into phytotoxic activity of interspecific potato hybrids with low glycoalkaloid contents

BackgroundGlycoalkaloids are bioactive compounds that contribute to the defence response of plants against herbivore attack and during pathogenesis. Solanaceous plants, including cultivated and wild potato species, are sources of steroidal glycoalkaloids. Solanum plants differ in the content and composition of glycoalkaloids in organs. In wild and cultivated potato species, more than 50 steroidal glycoalkaloids were recognized. Steroidal glycoalkaloids are recognized as potential allelopathic/phytotoxic compounds that may modify the growth of target plants. There are limited data on the impact of the composition of glycoalkaloids on their phytotoxic potential.ResultsThe presence of α-solasonine and α-solamargine in potato leaf extracts corresponded to the high phytotoxic potential of the extracts. Among the differentially expressed genes between potato leaf bulks with high and low phytotoxic potential, the most upregulated transcripts in sample of high phytotoxic potential were anthocyanin 5-aromatic acyltransferase-like and subtilisin-like protease SBT1.7-transcript variant X2. The most downregulated genes were carbonic anhydrase chloroplastic-like and miraculin-like. An analysis of differentially expressed proteins revealed that the most abundant group of proteins were those related to stress and defence, including glucan endo-1,3-beta-glucosidase acidic isoform, whose expression level was 47.96× higher in potato leaf extract with low phytotoxic.ConclusionsThe phytotoxic potential of potato leaf extract possessing low glycoalkaloid content is determined by the specific composition of these compounds in leaf extract, where α-solasonine and α-solamargine may play significant roles. Differentially expressed gene and protein profiles did not correspond to the glycoalkaloid biosynthesis pathway in the expression of phytotoxic potential. We cannot exclude the possibility that the phytotoxic potential is influenced by other compounds that act antagonistically or may diminish the glycoalkaloids effect.

β-1,3-Glucanases and chitinases participate in the stress-related defence mechanisms that are possibly connected with modulation of arabinogalactan proteins (AGP) required for the androgenesis initiation in rye (Secale cereale L.)

This work presents the biochemical, cytochemical and molecular studies on two groups of PR proteins, β-1,3-glucanases and chitinases, and the arabinogalactan proteins (AGP) during the early stages of androgenesis induction in two breeding lines of rye (Secale cereale L.) with different androgenic potential. The process of androgenesis was initiated by tillers pre-treatments with low temperature, mannitol and/or reduced glutathione and resulted in microspores reprogramming and formation of androgenic structures what was associated with high activity of β-1,3-glucanases and chitinases. Some isoforms of β-1,3-glucanases, namely several acidic isoforms of about 26 kDa; appeared to be anther specific. Chitinases were well represented but were less variable. RT-qPCR revealed that the cold-responsive chitinase genes Chit1 and Chit2 were expressed at a lower level in the microspores and whole anthers while the cold-responsive Glu2 and Glu3 were not active. The stress pre-treatments modifications promoted the AGP accumulation. An apparent dominance of some AGP epitopes (LM2, JIM4 and JIM14) was detected in the androgenesis-responsive rye line. An abundant JIM13 epitopes in the vesicles and inner cell walls of the microspores and in the cell walls of the anther cell layers appeared to be the most specific for embryogenesis.

Calponin-3 deficiency augments contractile activity, plasticity, fibrogenic response and Yap/Taz transcriptional activation in lens epithelial cells and explants

The transparent ocular lens plays a crucial role in vision by focusing light on to the retina with loss of lens transparency leading to impairment of vision. While maintenance of epithelial phenotype is recognized to be essential for lens development and function, knowledge of the identity of different molecular mechanisms regulating lens epithelial characteristics remains incomplete. This study reports that CNN-3, the acidic isoform of calponin, an actin binding contractile protein, is expressed preferentially and abundantly relative to the basic and neutral isoforms of calponin in the ocular lens, and distributes predominantly to the epithelium in both mouse and human lenses. Expression and MEKK1-mediated threonine 288 phosphorylation of CNN-3 is induced by extracellular cues including TGF-β2 and lysophosphatidic acid. Importantly, siRNA-induced deficiency of CNN3 in lens epithelial cell cultures and explants results in actin stress fiber reorganization, stimulation of focal adhesion formation, Yap activation, increases in the levels of α-smooth muscle actin, connective tissue growth factor and fibronectin, and decreases in E-cadherin expression. These results reveal that CNN3 plays a crucial role in regulating lens epithelial contractile activity and provide supporting evidence that CNN-3 deficiency is associated with the induction of epithelial plasticity, fibrogenic activity and mechanosensitive Yap/Taz transcriptional activation.

CSF SerpinA1 in Creutzfeldt-Jakob disease and frontotemporal lobar degeneration.

ObjectiveSerpinA1 (alpha‐1 antitrypsin) is an acute inflammatory protein, which seems to play a role in neurodegeneration and neuroinflammation. In Alzheimer’s disease and synucleinopathies, SerpinA1 is overexpressed in the brain and the cerebrospinal fluid (CSF) showing abnormal patterns of its charge isoforms. To date, no comprehensive studies explored SerpinA1 CSF isoforms in Creutzfeldt–Jakob disease (CJD) and frontotemporal lobar degeneration (FTLD).MethodsUsing a capillary isoelectric focusing immunoassay, we analyzed CSF SerpinA1 isoforms in control cases (n = 31) and patients with a definite or probable diagnosis of CJD (n=77) or FTLD (n = 30), belonging to several disease subtypes.ResultsThe overall SerpinA1 signal was significantly higher than in controls in CJD subtypes linked to abnormal prion protein (PrPSc) type 1, such as sporadic CJD (sCJD) MM(V)1, and in FTLD‐TDP. Moreover, CJD linked to PrPSc type 1 and FTLD‐TAU groups showed a significant relative increase of acidic and basic isoforms in comparison with controls, thereby forming two distinct SerpinA1 isoform profiles.InterpretationCJD linked to PrPSc type 1 and FTLD show a differential upregulation and post‐translational modifications of CSF SerpinA1. Further studies are needed to clarify whether these findings may reflect a common, albeit disease‐specific, pathogenetic mechanism related to neurodegeneration.

Acidic isoforms of Erwinase form part of the product: Correlation with clinical experience

Erwinia chrysanthemil-asparaginase (ErA) has been used for the treatment of acute lymphoblastic leukaemia (ALL) for decades, and its safety and efficacy have been well demonstrated. ErA drug substance and drug product contain a small proportion of acidic isoforms, with a known mechanism of formation, which have been shown to be minor conformational variants retaining enzymatic activity and function. Specifications for these acidic isoforms were set with an extremely limited data set, and with further manufacturing experience, it can now be demonstrated that they were set too tightly. Here, we consider the ability of the manufacturing process to meet the current acidic isoforms specifications, as well as clinical outcomes from drug product containing a higher proportion of isoforms. Compared with the historical clinical experience with the drug, there appeared to be no difference in the rate of adverse event reporting (e.g., hypersensitivity or other events) when drug product with relatively higher acidic isoforms was administered. ErA acidic isoforms comprise part of the ErA product and appear to have no clinical relevance, so a realignment of process capability and specification may be warranted. Biopharmaceutical developers should exercise caution when setting specifications with limited data, to avoid process capability pitfalls later.

PURIFICACIÓN Y ALGUNAS PROPIEDADES BIOQUÍMICAS Y MOLECULARES DE UNA NUEVA FOSFOLIPASA A2 NO MIOTÓXICA DEL VENENO DE LA SERPIENTE Bothrops atrox

Las fosfolipasas A2 (PLA2 ) del veneno de las serpientes, son enzimas con una variedad de efectos biológicos, debido a sus diferentes isoformas y algunas pudiendo ser miotoxinas. El objetivo de la investigación fue purificar, caracterizar y evaluar la actividad miotóxica de una isoforma de PLA2 ácida (BaPer-PLA2a). Se purificó por DEAE Sephadex-A50, Sephadex-G75 y un sistema automatizado de presión media-NGC. La BaPer-PLA2a tuvo una actividad específica de 34,1 U/mg y un peso molecular de ~14,5 kDa por PAGE-SDS en condiciones no reductoras. Del veneno se obtuvo el ARN total, para la síntesis de ADNc y un amplificado de ~480 pb. Se dedujo de la secuencia de ADNc una proteína madura de 124 aminoácidos con un punto isoeléctrico (4,41), siendo una isoforma ácida, asimismo presentó una estructura primaria con regiones conservadas y los residuos His48, Asp49 y Tyr52 identificados en el centro catalítico. Adicionalmente, el modelo teórico estructural posee una identidad mayor al 70 % con otras PLA2 ácidas. Finalmente, la BaPer-PLA2a no presenta actividad miotóxica, sin embargo, al combinarla con la isoforma de PLA2 básica incrementó la actividad miotoxina de esta última en 21,58 %.

Mid-manufacturing storage: Antibody stability after chromatography and precipitation based capture steps.

Antibodies of the IgG2 subclass were captured from the clarified cell culture fluid either by protein A chromatography or by polyethylene glycol precipitation. The captured intermediates were stored as neutralized eluates (protein A chromatography) or in solid form as polyethylene glycol precipitates over a period of 13 months at three temperatures, −20°C, 5°C, and room temperature to compare the capture technologies in regard of the resulting product storability. Monomer content, high molecular mass impurities product loss and changes in the composition of the charge variants were determined at six time points during the storage. At the beginning and end of the study, samples were additionally tested by differential scanning calorimetry, differential scanning fluorimetry, and circular dichroism to determine structural alterations occurring during storage. Protein A purified material was highly stable at all tested temperatures in regard of monomer content and product losses. A transient, acidic isoform was formed during the chromatography step which re‐converted to the main charged variant upon storage within a matter of days. Precipitated antibodies could be stored at −20 or 5°C for 3 months without product losses but afterwards recovery yields dropped to 65%. At room temperature, the precipitated antibody was not stable and degraded within 3 months.

Extended Stability of Reconstituted and Diluted SB3 (Trastuzumab Biosimilar) Assessed by Physicochemical and Biological Properties.

IntroductionStability information for the trastuzumab biosimilar SB3 is limited to 48 h at 2–8 °C for the reconstituted solution and 24 h at up to 30 °C for diluted solutions. Extended physicochemical stability and biological activity were assessed to evaluate the advanced preparation of reconstituted and diluted SB3.MethodsUnder controlled and aseptic conditions, the stability of reconstituted and diluted SB3 was evaluated using several assessments and according to the UK’s National Health Service guidance. Reconstituted SB3 was stored at 25 ± 2 °C with 60 ± 5% relative humidity for 3 days, and subsequently diluted SB3 (0.32–4 mg/mL) was stored in an infusion bag in the absence of light at 25 ± 2 °C with 60 ± 5% relative humidity for 28 days and 5 ± 3 °C for 28 days, respectively. Physicochemical stability (appearance, pH, protein concentration, size exclusion high-performance liquid chromatography, non-reducing capillary electrophoresis–sodium dodecyl sulfate, imaged capillary isoelectric focusing), biological activity (competitive inhibition binding assay to human epidermal growth factor receptor 2 by fluorescence resonance energy transfer, anti-proliferation assay), and properties with a potential safety impact (subvisible particulates, submicronic aggregation by dynamic light scattering) were determined.ResultsNo physicochemical instability signs or biological activity changes were observed for either reconstituted or diluted SB3 up to 28 days; all stability acceptance criteria were met. No major change was noted in the proportion of molecular weight variants (high molecular weight impurity, total purity) or relative percentages of acidic, main, and basic charge isoforms of the protein. No increases in particulates or aggregates in terms of a potential safety impact were noted.ConclusionThe physicochemical stability and biological activity of reconstituted and diluted SB3 are maintained for extended time periods beyond those denoted in the product labeling, which allows for advanced SB3 preparation and may reduce drug wastage and preparation time.FundingSamsung Bioepis Co., Ltd.

QUERCETIN OXIDATION BY KARELIAN BIRCH PEROXIDASE

The article presents the results of a study of peroxidase oxidation of quercetin in the xylem of 40‑year-old birch trees of 2 forms differing in wood texture – silver birch ( Betula pendula Roth var. pendula ) and Karelian birch ( B. pendula var. carelica (Mercl.) Hamet- Ahti), in the pH range of 4 to 10. Quercetin was used as a known model substrate for the study of peroxidase processes. The quercetin absorption maxima for the studied pH range were determined. The specific features of the reaction in acidic, neutral and alkaline media were considered for the studied objects. The time dependence of peroxidase activity is presented, as well as the pattern of peroxidase activity change in the pH range. Quercetin oxidation by peroxidase in the xylem of silver birch and Karelian birch was quantified. Acidic isoforms of the enzyme were shown to have higher activity compared to basic ones in both birch forms. In acidic conditions, peroxidase activity did not differ between silver and Karelian birch. In basic conditions, peroxidase activity was significantly higher in Karelian birch xylem. The resultant data generally indicate a higher oxidative capacity of peroxidase in Karelian birch xylem owing to a more active participation of all isoforms in the oxidation of quercetin. It is hypothesized that plant tissues with nonstandard enzymatic activity may be sources of biologically active substances and be used in biocatalysis processes.

Identification of methionine oxidation in human recombinant erythropoietin by mass spectrometry: Comparative isoform distribution and biological activity analysis

ABSTRACTBackground: Oxidative degradation of human recombinant erythropoietin (hrEPO) may occur in manufacturing process or therapeutic applications. This unfavorable alteration may render EPO inefficient or inactive. We investigated the effect of methionine/54 oxidative changes on the amino acid sequences, glycoform distribution and biological activity of hrEPO. Methods: Mass spectrometry was applied to verify the sequence and determine the methionine oxidation level of hrEPO. Isoform distribution was studied by capillary zone electrophoresis method. In vivo normocythemic mice assay was used to assess the biological activity of three different batches (A, B, and C) of the proteins. Results: Nano-LC/ESI/MS/MS data analyses confirmed the amino acid sequences of all samples. The calculated area percent of three isoforms (2–4 of the 8 obtained isoforms) were decreased in samples of C, B, and A with 27.3, 16.7, and 6.8% of oxidation, respectively. Specific activities were estimated as 53671.54, 95826.47, and 112994.93 mg/mL for the samples of A, B, and C, respectively. Conclusion: The observed decrease in hrEPO biological activity, caused by increasing methionine oxidation levels, was rather independent of its amino acid structure and mainly associated with the higher contents of acidic isoforms.

Separation of peroxidases from Miscanthus x giganteus, their partial characterisation and application for degradation of dyes

Due to wide applicative potential of peroxidases (POXs), the search for novel sources and forms, possibly with better characteristics and performances, is justified. In this study, POXs from Miscanthus x giganteus rhizomes grown in chernozem-like soil and mine tailings were examined. Higher activity of POXs in samples originating from the metal-contaminated soil was found. The quantity of acidic isoforms was much greater than basic. The rates of reactions catalysed by acidic POX isoforms decreased slightly at 50 °C, whereas stability of basic isoforms was affected at 40 °C. Concentrations of Zn, Mn and Fe were higher in rhizomes grown in mine tailings, and negatively correlated with the concentration of proteins. Basic POX isoforms effectively degraded CBB R250, while Amidoblack 10b was predominantly degraded by acidic isoforms. Thus, Miscanthus x giganteus can be used as a source of POXs which can be applied for dye decomposition and, possibly, waste water management.

Anti-platelet aggregation activity of two novel acidic Asp49-phospholipases A2 from Bothrops brazili snake venom

Phospholipases A2 (PLA2s) are important enzymes present in snake venoms and are related to a wide spectrum of pharmacological effects, however the toxic potential and therapeutic effects of acidic isoforms have not been fully explored and understood. Due to this, the present study describes the isolation and biochemical characterization of two new acidic Asp49-PLA2s from Bothrops brazili snake venom, named Braziliase-I and Braziliase-II. The venom was fractionated in three chromatographic steps: ion exchange, hydrophobic interaction and reversed phase. The isoelectric point (pI) of the isolated PLA2s was determined by two-dimensional electrophoresis, and 5.2 and 5.3 pIs for Braziliase-I and II were observed, respectively. The molecular mass was determined with values ​​of 13,894 and 13,869Da for Braziliase-I and II, respectively. Amino acid sequence by Edman degradation and mass spectrometry completed 87% and 74% of the sequences, respectively for Braziliase-I and II. Molecular modeling of isolated PLA2s using acid PLA2BthA-I-PLA2 from B. jararacussu template showed high quality. Both acidic PLA2s showed no significant myotoxic activity, however they induced significant oedematogenic activity. Braziliase-I and II (100μg/mL) showed 31.5% and 33.2% of cytotoxicity on Trypanosoma cruzi and 26.2% and 19.2% on Leishmania infantum, respectively. Braziliase-I and II (10μg) inhibited 96.98% and 87.98% of platelet aggregation induced by ADP and 66.94% and 49% induced by collagen, respectively. The acidic PLA2s biochemical and structural characterization can lead to a better understanding of its pharmacological effects and functional roles in snakebites pathophysiology, as well as its possible biotechnological applications as research probes and drug leads.