Enzyme Complex Research Articles

Epigenetic therapies targeting histone lysine methylation: complex mechanisms and clinical challenges.

As epigenetic therapies continue to gain ground as potential treatment strategies for cancer and other diseases, compounds that target histone lysine methylation and the enzyme complexes represent a major frontier for therapeutic development. Clinically viable therapies targeting the activities of histone lysine methyltransferases (HKMT) and demethylases (HKDMs) have only recently begun to emerge following FDA approval of the EZH2 inhibitor tazemetostat in 2020 and remain limited to compounds targeting the well-studied SET domain-containing HKMTs and their opposing HKDMs. These include the H3K27 methyltransferases EZH2/EZH1, the singular H3K79 methyltransferase DOT1L, and the H3K4 methyltransferase MLL1/COMPASS as well as H3K9 and H3K36 methyltransferases. They additionally include the H3K4/9-preferential demethylase LSD1 and the H3K4-, H3K27-, and H3K36-preferential KDM5, KDM6, and KDM2 demethylase subfamilies, respectively. This Review discusses the results of recent clinical and preclinical studies relevant to all of these existing and potential therapies. It provides an update on advancements in therapeutic development, as well as more basic molecular understanding, within the past 5 years approximately. It also offers a perspective on histone lysine methylation that departs from the long-predominant "histone code" metaphor, emphasizing complex-disrupting inhibitors and proximity-based approaches rather than catalytic domain inhibitors in the outlook for future therapeutic development.

Synthesis, characterization and molecular modeling approach of hybrid pyrazole based thiazolidinone derivatives: An estimation and inhibition of diabetes mellitus

Diabetes Mellitus (DM), a persistent metabolic disorder was the focus of study in current research work. A novel series of pyrazole based thiazolidinone derivatives (1–15) was designed and efficiently synthesized for the treatment of DM. All the novel synthesized compounds were investigated for their biological inhibitory potential against alpha-amylase and alpha-glucosidase in comparison to standard drug acarbose (IC50 = 7.20±0.10µM and 8.10±0.20µM). Analogue 8 (IC50 = 6.20±0.20 and 6.80±0.40µM) demonstrated spellbinding inhibition potential surpassing the potency of standard drug. This remarkable potency of the compound 8 is due to the presence of trifluoromethyl moiety, which interacts with amino acids on receptor proteins via strong hydrogen bond. All these interactions were also visualized under in-silico molecular docking study, which revealed the insight into the binding interaction of potent compounds against target enzyme complex. Additionally, to assess drug-likeness and other pharmacokinetic properties of the potent compounds, ADME analysis was also conducted. Moreover, all the synthesized compounds were structurally analyzed via spectral studies comprising of 1H NMR, 13C NMR and HREI-MS.

Food as a factor determining the physiological state of populations of the phytopagous pests of agricultural crops

Relevance. Trophic relationships along with competition and mutualism are the most basic and significant interactions in ecosystems. To develop, survive, and multiply, insects need to consume a certain amount of nutrients at a certain ratio. Food products are complex mixes of nutrients and non-nutritive substances (sometimes toxic ones): macronutrients (proteins, carbohydrates, and lipids), micronutrients (vitamins and minerals), and water. Some nutrients are essential; insects lack the ability to synthesize them in their bodies and must obtain them from their diet or through symbiosis with beneficial organisms. Identification mechanisms being well developed in the system “phytophagous insect – plant” allow insects to successfully spread, multiply, and feed on certain plant species. The complex of hydrolytic enzymes in the insect intestine is one of the main targets for plant defense responses because these enzymes determine the availability of structural compounds for phytophagous insects. For this reason, enzymes in the insect intestine play a key role in the adaptation of insects to the pest resistance of fodder plants. For instance, when proteinase inhibitors are synthesized in a fodder plant as the result of induced insect resistance the complex of enzymes in an insect intestine might change negating the effect of these inhibitors. The development of co-adaptations due to interactions among species in food chains depends on a complicated constellation of conflicting relationships between consumers and food objects. The mechanisms of this influence may be rooted in the allelochemical interactions in the system “phytophagous insect – plant recipient”. Allelopathic interactions are among the most complex interactions because they are constituted by direct and indirect effects. Plants when damaged by phytophagous insects activate defense responses, which incorporate several mechanisms, including an increase in the concentration of secondary metabolites, many of which are phenolic compounds.The aim of the work is to describe the mechanisms of relationships in the system “phytophage-plant”. Conclusion. Management of processes of intra-water divergence of insect-phytophages in agrobiocoenoses in order to prevent the emergence of races and populations of pests adapted to live on initially resistant to them plant forms is possible in compliance with the transition to a targeted selection of agricultural crops for resistance to a complex of pests.

Biallelic variants in MRPL49 cause variable clinical presentations, including sensorineural hearing loss, leukodystrophy, and ovarian insufficiency.

Combined oxidative phosphorylation deficiency (COXPD) is a rare multisystem disorder which is clinically and genetically heterogeneous. Genome sequencing identified biallelic MRPL49 variants in individuals from five unrelated families with presentations ranging from Perrault syndrome (primary ovarian insufficiency and sensorineural hearing loss) to severe childhood onset of leukodystrophy, learning disability, microcephaly and retinal dystrophy. Complexome profiling of fibroblasts from affected individuals revealed reduced levels of the small and, a more pronounced reduction of, the large mitochondrial ribosomal subunits. There was no evidence of altered mitoribosomal assembly. The reductions in levels of OXPHOS enzyme complexes I and IV are consistent with a form of COXPD associated with biallelic MRPL49 variants, expanding the understanding of how disruption of the mitochondrial ribosomal large subunit results in multi-system phenotypes.

A Versatile Method to Create Antibody/Split‐Enzyme Complexes and Its Application to a Rapid, Homogeneous, and Universal Electrochemical Immunosensing System

AbstractIn this study, a versatile method is developed to create an antibody/split‐enzyme complex for use in electrochemical immunosensors. SpyCatchers are genetically fused at each terminus of flavin adenine dinucleotide‐dependent glucose dehydrogenase (FAD‐GDH) and a protease recognition sequence is inserted into a loop region to prepare a soluble protein and the split GDH. SpyTag‐fused single‐chain variable fragments (scFvs) are employed, which leads to the simple preparation of antibody‐split enzyme complexes (split AECs). The addition of pentameric C‐reactive protein (CRP), as a representative multimeric protein, restored the GDH activity of the split AECs, as the two split AEC fragments formed active GDH when in close proximity. CRP in human serum is electrochemically detected within 5 min without any washing steps with a clinically relevant CRP detection range (0.03–1 mg dL−1). The detection system is expanded to detect hemoglobin, SARS‐CoV‐2 spike protein, and inactivated SARS‐CoV‐2 by exchanging the scFvs. These results show that the convenient preparation method of the split GDH and the split AEC by the insertion of the protease recognition sequence and the use of SpyCatcher/SpyTag can realize a rapid, homogeneous, and universal electrochemical detection system that can be integrated into a commercially available electrochemical glucose sensor.

Connecting the Dots: Telomere Shortening and Rheumatic Diseases.

Telomeres, repetitive sequences located at the extremities of chromosomes, play a pivotal role in sustaining chromosomal stability. Telomerase is a complex enzyme that can elongate telomeres by appending telomeric repeats to chromosome ends and acts as a critical factor in telomere dynamics. The gradual shortening of telomeres over time is a hallmark of cellular senescence and cellular death. Notably, telomere shortening appears to result from the complex interplay of two primary mechanisms: telomere shelterin complexes and telomerase activity. The intricate interplay of genetic, environmental, and lifestyle influences can perturb telomere replication, incite oxidative stress damage, and modulate telomerase activity, collectively resulting in shifts in telomere length. This age-related process of telomere shortening plays a considerable role in various chronic inflammatory and oxidative stress conditions, including cancer, cardiovascular disease, and rheumatic disease. Existing evidence has shown that abnormal telomere shortening or telomerase activity abnormalities are present in the pathophysiological processes of most rheumatic diseases, including different disease stages and cell types. The impact of telomere shortening on rheumatic diseases is multifaceted. This review summarizes the current understanding of the link between telomere length and rheumatic diseases in clinical patients and examines probable telomere shortening in peripheral blood mononuclear cells and histiocytes. Therefore, understanding the intricate interaction between telomere shortening and various rheumatic diseases will help in designing personalized treatment and control measures for rheumatic disease.

Structural elucidation of recombinant Trichomonas vaginalis 20S proteasome bound to covalent inhibitors

The proteasome is a proteolytic enzyme complex essential for protein homeostasis in mammalian cells and protozoan parasites like Trichomonas vaginalis (Tv), the cause of the most common, non-viral sexually transmitted disease. Tv and other protozoan 20S proteasomes have been validated as druggable targets for antimicrobials. However, low yields and purity of the native proteasome have hindered studies of the Tv 20S proteasome (Tv20S). We address this challenge by creating a recombinant protozoan proteasome by expressing all seven α and seven β subunits of Tv20S alongside the Ump-1 chaperone in insect cells. The recombinant Tv20S displays biochemical equivalence to its native counterpart, confirmed by various assays. Notably, the marizomib (MZB) inhibits all catalytic subunits of Tv20S, while the peptide inhibitor carmaphycin-17 (CP-17) specifically targets β2 and β5. Cryo-electron microscopy (cryo-EM) unveils the structures of Tv20S bound to MZB and CP-17 at 2.8 Å. These findings explain MZB’s low specificity for Tv20S compared to the human proteasome and demonstrate CP-17’s higher specificity. Overall, these data provide a structure-based strategy for the development of specific Tv20S inhibitors to treat trichomoniasis.

Двусторонняя посттромботическая ретинопатия как проявление ретиноваскулита на фоне генетически обусловленной тромбофилии

Purpose. To analyze current literature data on the topic of thrombotic and vasoocclusive lesions of retinal vessels in conditions of thrombophilia and endotheliopathy to determine the tactics of management of patients with this pathology. Material and methods. A search and analysis of current research published in the databases PubMed, eLibrary, Springer, ScienceDirect and Google Scholar has been performed. A clinical case of bilateral postthrombotic retinopathy with the phenomena of vasculitis and fibrovascular proliferation, which developed against the background of thrombophilia in a 34-year-old woman, is also described. Results. Retinal vasoocclusion occurred in conditions of thrombophilia due to hyperproduction of factor VIII and von Willebrand factor (vWF), in the presence of genetic markers of thrombogenic risk and a history of pulmonary embolism. Mutations F13, PAI-1, FBG, ITGA2 and ITGB3 demonstrate a moderate association with vasoocclusive retinal damage, while the genes of the folate complex enzymes MTRR and MTHFR are associated with thrombophilia due to hyperhomocysteinemia, endotheliopathy and the development of heart defects that increase the risk of occlusion of the CRV and its branches. Dynamic assessment of the condition of retinal vessels according to optical coherence tomography in angiography mode allowed us to confirm the effectiveness of antiVEGF therapy in combination with panretinal laser coagulation, which was accompanied by the restoration of lost visual functions. Conclusion. In order to prevent retinal vascular catastrophes for patients with a similar comorbid background, it is preferable to use multi-stage transpuppillary retinal laser coagulation and anti-VEGF therapy, thereby avoiding vitreoretinal surgical interventions to limit intraoperative and postoperative complications. Key words: postthrombotic retinopathy, neoangiogenesis, thrombophy

Structural Analysis and Substrate Specificity of D-Carbamoylase from Pseudomonas.

The synthesis of enantiomeric forms of D-amino acids can be achieved by a two-step "hydantoinase process" based on the sequential catalysis of substrates by specific enzymes, D-carbamoylase and D-hydantoinase. Here, we describe the structural features of D-carbamoylase from Pseudomonas, the encoded gene of which was chemically synthesized and cloned into Escherichia coli. A significant fraction of the overexpressed recombinant protein forms insoluble inclusion bodies, which are partially converted to a soluble state upon treatment with N-lauroylsarcosine or upon incubation of cells at 28 °C. Purified His-tagged protein exhibits the highest activity towards N-carbamoyl-D-alanine and N-carbamoyl-D-tryptophan. Comprehensive virtual analysis of the interactions of bulky carbamylated amino acids with D-carbamoylase provided valuable information. Molecular docking analysis revealed the location of the substrate binding site in the three-dimensional structure of D-carbamoylase. Molecular dynamics simulations showed that the binding pocket of the enzyme in complex with N-carbamoyl-D-tryptophan was stabilized within 100 nanoseconds. The free energy data showed that Arg176 and Asn173 formed hydrogen bonds between the enzyme and substrates. The studies of D-carbamoylases and the properties of our previously obtained D-hydantoinase suggest the possibility of developing a harmonized biotechnological process for the production of new drugs and peptide hormones.

LRRK2 regulates production of reactive oxygen species in cell and animal models of Parkinson's disease.

Oxidative stress has long been implicated in Parkinson's disease (PD) pathogenesis, although the sources and regulation of reactive oxygen species (ROS) production are poorly defined. Pathogenic mutations in the gene encoding leucine-rich repeat kinase 2 (LRRK2) are associated with increased kinase activity and a greater risk of PD. The substrates and downstream consequences of elevated LRRK2 kinase activity are still being elucidated, but overexpression of mutant LRRK2 has been associated with oxidative stress, and antioxidants reportedly mitigate LRRK2 toxicity. Here, using CRISPR-Cas9 gene-edited HEK293 cells, RAW264.7 macrophages, rat primary ventral midbrain cultures, and PD patient-derived lymphoblastoid cells, we found that elevated LRRK2 kinase activity was associated with increased ROS production and lipid peroxidation and that this was blocked by inhibitors of either LRRK2 kinase or NADPH oxidase 2 (NOX2). Oxidative stress induced by the pesticide rotenone was ameliorated by LRRK2 kinase inhibition and was absent in cells devoid of LRRK2. In a rat model of PD induced by rotenone, a LRRK2 kinase inhibitor prevented the lipid peroxidation and NOX2 activation normally seen in nigral dopaminergic neurons in this model. Mechanistically, LRRK2 kinase activity was shown to regulate phosphorylation of serine-345 in the p47phox subunit of NOX2. This, in turn, led to translocation of p47phox from the cytosol to the membrane-associated gp91phox (NOX2) subunit, activation of the NOX2 enzyme complex, and production of ROS. Thus, LRRK2 kinase activity may drive cellular ROS production in PD through the regulation of NOX2 activity.

Evolutionary origins and innovations sculpting the mammalian PRPS enzyme complex.

The phosphoribosyl pyrophosphate synthetase (PRPS) enzyme conducts a chokepoint reaction connecting central carbon metabolism and nucleotide production pathways, making it essential for life1,2. Here, we show that the presence of multiple PRPS-encoding genes is a hallmark trait of eukaryotes, and we trace the evolutionary origins and define the individual functions of each of the five mammalian PRPS homologs - three isozymes (one testis-restricted)3,4 and two non-enzymatic associated proteins (APs)5,6 - which we demonstrate operate together as a large molecular weight complex capable of attaining a heterogeneous array of functional multimeric configurations. Employing a repertoire of isogenic fibroblast clones in all viable individual or combinatorial assembly states, we define preferential interactions between subunits, and we show that cells lacking PRPS2, PRPSAP1, and PRPSAP2 render PRPS1 into aberrant homo-oligomeric assemblies with diminished metabolic flux and impaired proliferative capacity. We demonstrate how numerous evolutionary innovations in the duplicated genes have created specialized roles for individual complex members and identify translational control mechanisms that enable fine-tuned regulation of PRPS assembly and activity, which provide clues into the positive and negative selective pressures that facilitate metabolic flexibility and tissue specialization in advanced lifeforms. Collectively, our study demonstrates how evolution has transformed a single PRPS gene into a multimeric complex endowed with functional and regulatory features that govern cellular biochemistry.

Effect of Moderate and Acute Hypoxia on the Antioxidant Enzyme Complex of the Tissues of the Black Sea Mussel Mytilus galloprovincialis

Effect of Moderate and Acute Hypoxia on the Antioxidant Enzyme Complex of the Tissues of the Black Sea Mussel Mytilus galloprovincialis

Biological active compounds from edible mushroom: Effect on hela cells

Background: Mushrooms are unique organisms rich in proteins, carbohydrates, vitamins, and minerals, which allows them to be used not only as a source of nutrition but also in cosmetics and medicine. The fungus P. ostreatus possesses two strong enzymatic complexes – lignin-decaying and cellulose-decaying. Objective: The research aimed to study the antitumor activity of treated mm-wave mycelial extracts of mushrooms on the HeLa cell line. Research on edible mushrooms against tumors is very actual and important for the field of functional food science and bioactive compounds field. Methods: The effect of the fungal culture extract on the cyto-photometric and morphometric indices of the HeLa cell line culture was studied according to the nature of proliferation and transcription of malignant tissues. Using high-resolution liquid chromatography, the amino acid composition of acid-soluble proteins in mycelial extracts of a mushroom culture treated with mm waves was studied. Results: Extracts of P. ostreatus mycelial culture significantly suppressed the growth of proliferative activity of human tumor cultures and completely suppressed the mitotic activity of continuous HeLa cell cultures to 72 hours. Our study revealed a significant increase in glutamic and aspartic acids in mycelial culture extracts treated by mm-waves. Conclusion: Based on HPLC analysis, we suggest polyfunctional peroxidase as the candidate for the role of biologically active compound in the composition of aqueous extracts of the mycelial culture. So, the polyfunctional peroxidase plays an active role in the therapeutic properties of the oyster mushroom. Keywords: anticancer activity, ant-inflammation activity, mm-waves, mushroom`s, mycelial extracts, HPLC of acid-soluble proteins, HeLa cell line.

Effect of mitochondrial coenzyme-Q10 precursor solanesol in gentamicin-induced experimental nephrotoxicity: Evidence from restoration of ETC-complexes and histopathological alterations.

Nephrotoxicity occurs when the body is exposed to certain drugs or toxins. When kidney damage occurs, the kidney fails to eliminate excess urine and waste. Solanesol (C45H74O) is a tri-sesquiterpenoid alcohol first isolated from tobacco, and it is widely distributed in plants of the Solanaceae family. Solanesol (SNL) is an intermediate in the synthesis of coenzyme Q10 (CoQ10), an antioxidant which protects nerve cells. This study investigated the protective effect of SNL at doses of 30 and 60 mg/kg in gentamicin-induced nephrotoxicity in Wistar albino rats. Animals were distributed into six groups and administered 100 mg/kg gentamicin-intraperitoneal injection for 14 days. Biochemical assessments were performed on kidney homogenate, blood, and serum. Treatment with SNL was shown as lower serum levels of creatinine, blood urea nitrogen (BUN), thiobarbituric acid reactive substances (TBARS), and Tumor necrosis factor alpha)TNF-α ((p < .001). It also restored reduced glutathione (GSH) and mitochondrial complex enzymatic activity as protective measures against gentamicin-induced nephrotoxicity. SNL were shown to reduce inflammation and oxidative stress markers (p < .001). Histological findings furtherly augmented the protective effects of SNL. Long-term SNL therapy also restored mitochondrial electron transport chain complex enzymes, such as complex-I (p < .001). In conclusion, these findings suggest that SNL can represent a protective therapeutic option for drug-induced nephrotoxicity, a long-term adverse effect of aminoglycoside antibiotics such as gentamicin.

In vitro Study of Biofilm Sensitivity of to the Enzyme Complex Included in Wobenzym

Background. Bacterial films are a marker of chronic recurrent infections. Biofilms on mucous membranes block the inflammatory response of the macroorganism, suppressing the activity of immunocytes, and thereby allow microorganisms to reach high concentrations. Currently, research is being conducted to find medications that can act on biofilms. Enzymes, especially their complexes, are substances that can destroy bacterial films. Objective. Еo determine in vitro the sensitivity of bacterial biofilms formed by vaginal microorganisms to the complex of enzymes included in Wobenzym. Materials and methods. The study included 72 clinical isolates of pure microorganism cultures isolated from the vaginal biotope: Gardnerella vaginalis (3), Enterococcus faecalis (9), Escherichia coli (18), Klebsiella pneumoniae (15), Klebsiella aerogenes (3), Lactobacillus crispatus (3), Streptococcus pyogenes (3), Acinetobacter baumanii (3), Staphylococcus aureus (3), Candida albicans (3), Enterococcus faecium (3), Streptococcus agalactiae (3), Lactobacillus acidophilus (3). Bacterial biofilm formation was determined in polystyrene flat-bottom plates using a modified method of Christensen et al. (1985). The tablet form of Wobenzym was used in the study. The tablet shell was washed with saline, the tablet itself was dissolved in 10 ml of 0.9% NaCl and used for in vitro studies. The result was determined using a reader on a spectrophotometer to determine the optical density (OD) of the formed biofilm. It was believed that the drug acted on the bacterial film, reducing the OD by more than three times. Results. An in vitro study revealed clinical isolates of bacteria that formed biofilms of varying severity. Of the 72 clinical bacterial isolates, 38 formed biofilms. A pronounced effect of the complex of enzymes included in Wobenzym on biofilms formed by microorganisms such as A. baumanii, S. aureus, G. vaginalis and E. faecalis was noted. Conclusion. Wobenzym has an effective destructive effect on biofilms formed by various microorganisms, including G. vaginalis, common causative agents of bacterial vaginosis, as well as staphylococci and enterococci, causative agents of aerobic (nonspecific) vaginitis. Conclusion. The drug Wobenzym has an effective destructive effect on biofilms formed by various microorganisms, including Gardnerella vaginalis, common causative agents of bacterial vaginosis, as well as staphylococci and enterococci, causative agents of aerobic (nonspecific vaginitis).

Synthesis and performance evaluation of polymer-ceramic composite microcapsules as reservoir protectant for natural gas hydrate drilling.

Natural gas hydrate is a promising unconventional natural gas source due to its high energy density and huge global reserves. During exploitation, the drilling fluid may invade the hydrate formation and induce hydrate decomposition, causing reservoir damage. Herein, a novel reservoir protectant made by bio-degradable temporary plugging material (BDTPM) was developed in the form of polymer-ceramic composite microcapsules. As an additive to the drilling fluid, the BDTPM can minimize drilling fluid intrusion by plugging the reservoir during drilling and afterwards maximize permeability recovery by degrading the material. The particle size distribution was in the range of 1-130μm. The optimal mass ratio between modified ceramic particles, ethyl cellulose and epoxy resin was found to be 4:2:1. The plugging rate was 100% when ethyl cellulose and epoxy resin were mixed to coat the ceramic particles to form BDTPM, and the plugging performance was the best. At a temperature close to the typical hydrate reservoir environment (5°C), 0.02 wt% low-temperature complex enzyme can degrade BDTPM, and the permeability recovery rate is 64.66%. The efficient reservoir protectant developed in this work could play an important role in the successful drilling of natural gas hydrate reservoirs.

Unravelling of cellulolytic fungal consortium from humus soil for efficient lignocellulosic waste degradation

Cellulose is a complex polysaccharide composed of β 1, 4 glycosidic linkages and these linkages are broken down by a complex enzyme system called cellulase. Cellulase is an enzyme complex associated with β 1, 4 endoglucanase, β 1, 4 exoglucanase, and β glucosidase. The fungal strains were isolated from decomposed humus soil and screened for the best cellulolytic activity. Thirty-two isolates were screened among these; three were selected based on their morphological characters and hydrolytic capacity, viz, Cladosporium oxysporum N5, Aspergillus sigurros N6, and Cladosporium cladosporioides N12. Among these fungi, Cladosporium oxysporum N5 shows potential hydrolytic activity and was selected for optimization studies and evaluation of their cellulolytic capability. Cellulolytic strain Cladosporium oxysporum N5 produced maximum amount of cellulase enzyme at 5 days of incubation at 30 ℃ and pH 7, viz, β 1, 4 endoglucanase (167.83± U/ml), β 1, 4 exoglucanase (29.04± U/ml), and β glucosidase (34.07± U/ml). SEM coupled Energy dispersive X-ray and FTIR spectroscopy methods revealed the cellulose degradation efficiency of fungal cellulase by microscopic, elemental percentage, and functional group, respectively. An affordable and eco-friendly fungal-based cellulase that will boost industrially important commodity production such as food, beverages, pharmaceuticals, fertilisers, and biofuels.

Identification of a Fomitopsis pinicola from Xiaoxing’an Mountains and Optimization of Cellulase Activity

Brown-rot fungi are large fungi that can decompose the cell walls of wood; they are notable for their secretion of diverse and complex enzymes that synergistically hydrolyze natural wood cellulose molecules. Fomitopsis pinicola (F. pinicola) is a brown-rot fungus of interest for its ability to break down the cellulose in wood efficiently. In this study, through a combination of rDNA-ITS analysis and morphological observation, the wood decay pathogen infecting Korean pine (Pinus koraiensis Siebold and Zucc.) was identified. Endoglucanase (CMCase) and β-glucosidase were quantified using the DNS (3,5-Dinitrosalicylic acid) method, and the cellulase activity was optimized using a single-factor method and orthogonal test. The results revealed that the wood-decaying fungus NE1 identified was Fomitopsis pinicola with the ITS accession number OQ880566.1. The highest cellulase activity of the strain reached 116.94 U/mL under the condition of an initial pH of 6.0, lactose 15 g·L−1, KH2PO4 0.5 g·L−1, NH4NO3 15 g·L−1, MgSO4 0.5 g·L−1, VB1 0.4 g·L−1, inoculated two 5 mm fungal cakes in 80 mL medium volume cultured 28 °C for 5 days. This laid a foundation for improving the degradation rate of cellulose and biotransformation research, as well as exploring the degradation of cellulose by brown rot fungi.

Action of Enzyme Complex on Bioactive Components Extracted from Soy Residue (Okara)

Action of Enzyme Complex on Bioactive Components Extracted from Soy Residue (Okara)

A high-efficiency strategy for fruit preservation using green, natural raw materials

Straw is an abundant renewable biomass resource material. Lignin contained in straw is a unique natural aromatic compound in nature. At present, it is urgent to find ways to realize the higher value of natural lignin resources. In this study, alkali lignin was separated from rice straw by hydrothermal method in NaOH solution, which was prepared lignin nanoparticles by a simple green anti-solvent method. The obtained lignin nanoparticles had excellent anti-tyrosinase activity (IC50 = 0.329 mg mL−1) and anti-oxidation performance (IC50 = 0.0451 mg mL−1). Meanwhile, through the analysis of tyrosinase inhibition kinetics, it is concluded that the tyrosinase inhibition by lignin nanoparticles belongs to mixed inhibition. The affinity of lignin nanoparticles to the free enzyme is greater than that of enzyme and substrate complex. In addition, lignin nanoparticles were added to chitosan solution for compounding, then the composite films for fruit preservation were prepared by casting method. The experimental results show that the composite membrane can effectively extend the shelf life of fruits, which is expected to achieve a broader application in the field of fruit preservation and food packaging.