Acid Oxidase Enzyme Research Articles

D-serine and D-amino acid oxidase levels in patients with schizophrenia spectrum disorders in the first episode and 6-month follow-up

BackgroundD-serine and the D-amino acid oxidase (DAO) enzyme, which breaks down d-amino acids, may be involved in the pathophysiology of schizophrenia by affecting the N-methyl-D-aspartate (NMDA) receptor. The exact role of D-serine and DAO, as well as the consequences of increased DAO activity in patients with schizophrenia, remain unclear. We aimed to investigate D-serine and DAO levels in patients with first-episode schizophrenia spectrum disorders before treatment and after six months of treatment. MethodComparisons for the serum levels of D-serine and DAO were made between 81 healthy controls and 89 patients with first-episode schizophrenia spectrum disorders without a history of treatment. Further comparisons were made after 6 months for changes in these levels in the 41 patients in follow-up. The Positive and Negative Syndrome Scale (PANNS), Calgary Scale for Depression in Schizophrenia (CDSS), Montreal Cognitive Assessment Scale (MoCA), Global Assessment Scale (GAS), and Clinical Global Impression Scale (CGI) were used to evaluate the symptom severity and functionality. Secondary results included comparisons related to antipsychotic equivalent doses. ResultsBefore treatment, patients had significantly lower levels of D-serine, DAO, and D-serine/DAO ratio compared to healthy individuals (p < 0.001; p < 0.001; p = 0.004). DAO and D-serine levels of the patients were higher after six months of treatment (p = 0.025; p = 0.001). There was correlation of DAO levels with antipsychotic dosage and with PANSS negative and total subscale scores (rho = 0.421, p = 0.01; rho = 0.280, p = 0.008; rho = 0.371, p = 0.000). No correlation was found between serum D-serine level, DAO level, and the D-serine/DAO ratio with cognitive function. ConclusionsThe results suggest that D-serine and DAO may play a role that is sensitive to treatment effects in schizophrenia spectrum disorders. To gain a more comprehensive understanding of the impact antipsychotic drugs have on NMDA receptor dysfunction, there is a requirement for studies that directly evaluates the activity of the DAO enzyme.

Correlation Analysis of Key Residue Sites between Computational-Aided Design Thermostability d-Amino Acid Oxidase and Ancestral Enzymes.

The d-amino acid oxidase (DAAO) from Rhodotorula taiwanensis has proven to have great potential for applications due to its excellent catalytic kinetic parameters. However, its poor thermal stability has limited its performance in biocatalysis. Herein, starting from the variant SHVG of RtwDAAO, this study employed a comprehensive computational design approach for protein stability engineering, resulting in positive substitutions at specific sites (A43S, T45M, C234L, E195Y). The generated variant combination, SHVG/SMLY, exhibited a significant synergistic effect, leading to an extension of the half-life and Tmapp. The ancestral sequence reconstruction revealed the conservation of the variant sites. The association of the variant sites with the highly stable ancestral enzyme was further explored. After determining the contribution of the variant sites to thermal stability, it was applied to other homologous sequences and validated. Molecular dynamics simulations indicated that the increased hydrophobicity of the variant SHVG/SMLY was a key factor for the increased stability, with strengthened intersubunit interactions playing an important role. In addition, the physical properties of the amino acids themselves were identified as crucial factors for thermal stability generality in homologous enzymes, which is important for the rapid acquisition of a series of stable enzymes.

EFFECT OF TEMPERATURE ON THE PROTEIN PROFILE OF MACROVIPERA LEBETINUS (BLUNT-NOSED VIPER) VENOM: A PRELIMINARY STUDY

Snake venom is a complex biological fluid consisting mainly of proteins and peptides possessing diverse biological activities. Snake venoms draw attention due to their bioactive proteins/peptides with therapeutic and diagnostic potential. Testing the stability of snake venom proteins under different conditions including temperature provides useful data for venom research. Macrovipera lebetinus, blunt-nosed viper, is the biggest viper species of Türkiye distributed mainly in eastern and southeastern Anatolia. Although its venom components were investigated before, there is limited data regarding the effect of temperature on its venom proteins. The present study aimed to investigate the effect of temperature on the venom proteins of M. lebetinus. For this purpose, venom samples were incubated at 25, 37, and 50°C. Thereafter, venom proteins were separated by two-dimensional gel electrophoresis (2D-PAGE) method. Some qualitative and quantitative differences in the protein profile indicating structural changes and degradation were observed especially after 50°C treatment. It has been found that the protein spots most affected by temperature will most likely contain metalloproteinase, phospholipase A2 and ʟ-amino acid oxidase enzymes, by comparing the experimental molecular weight and pI values with those in the literature. Detailed studies including enzyme activities and toxicity assays will provide more data on the stability of M. lebetinus venom under different conditions.

Sodium benzoate attenuates 2,8-dihydroxyadenine nephropathy by inhibiting monocyte/macrophage TNF-α expression

Sodium benzoate (SB), a known D-amino acid oxidase (DAO) enzyme inhibitor, has an anti-inflammatory effect, although its role in renal damage has not been explored. 2,8-dihydroxyadenine crystal induced chronic kidney disease, in which TNF-α is involved in the pathogenesis, was established by oral adenine administration in C57BL/6JJcl mice (AdCKD) with or without SB to investigate its renal protective effects. SB significantly attenuated AdCKD by decreasing serum creatinine and urea nitrogen levels, and kidney interstitial fibrosis and tubular atrophy scores. The survival of AdCKD mice improved 2.6-fold by SB administration. SB significantly decreased the number of infiltrating macrophages observed in the positive F4/80 immunohistochemistry area and reduced the expression of macrophage markers and inflammatory genes, including TNF-α, in the kidneys of AdCKD. Human THP-1 cells stimulated with either lipopolysaccharide or TNF-α showed increased expression of inflammatory genes, although this was significantly reduced by SB, confirming the anti-inflammatory effects of SB. SB exhibited renal protective effects in AdCKD in DAO enzyme deficient mice, suggesting that anti-inflammatory effect of SB was independent of DAO enzyme activity. Moreover, binding to motif DNA sequence, protein level, and mRNA level of NF-κB RelB were significantly inhibited by SB in AdCKD kidneys and lipopolysaccharide treated THP-1 cells, respectively. We report that anti-inflammatory property of SB is independent of DAO enzymatic activity and is associated with down regulated NF-κB RelB as well as its downstream inflammatory genes such as TNF-α in AdCKD.

Stemphylium lycopersici and Stemphylium solani improved antioxidant system of soybean under chromate stress

Ecologists around the world are giving great attention to the metal pollution of agronomic soil. Recently, several techniques have been employed to remediate heavy metals, but the use of microorganisms is cheap, less time-consuming, and easily available. In the current study, the endophytic strains, Cp1 and Cp2 were isolated from sterilized 1-5 cm long root and leaf segments of Chlorophytum comosum using Hagem media. To get pure colonies, the strains were repeatedly cultured on potato dextrose agar (PDA) media. The strains Cp1 and CP2 were identified as Stemphylium lycopersici and Stemphylium solani based on ITS sequencing and neighbor joining (NJ) method. Both strains showed a growth-promoting potential in soybean seedlings exposed to chromate (Cr) stress. Moreover, S. lycopersici and S. solani improved the Indole-3-acetic acid (IAA), flavonoids, phenolics, protein, and proline contents, whereas, lowered Salicylic acid (SA) production in the seedlings. The selected endophytic fungal strains also promoted the antioxidant system of soybean seedlings through enhanced production of ascorbic acid oxidase (AAO), catalases (CAT), peroxidase, and free radical scavenging enzymes. Both strains bio-transformed the toxic Cr-VI to less toxic Cr-III in the cultural filtrate as well as host plants. In fact, efficient uptake of Cr and its conversion by the isolated endophytic fungal strains could be used as a viable tool to remediate Cr contamination in agricultural soils.

Rational and Translational Implications of D-Amino Acids for Treatment-Resistant Schizophrenia: From Neurobiology to the Clinics.

Schizophrenia has been conceptualized as a neurodevelopmental disorder with synaptic alterations and aberrant cortical–subcortical connections. Antipsychotics are the mainstay of schizophrenia treatment and nearly all share the common feature of dopamine D2 receptor occupancy, whereas glutamatergic abnormalities are not targeted by the presently available therapies. D-amino acids, acting as N-methyl-D-aspartate receptor (NMDAR) modulators, have emerged in the last few years as a potential augmentation strategy in those cases of schizophrenia that do not respond well to antipsychotics, a condition defined as treatment-resistant schizophrenia (TRS), affecting almost 30–40% of patients, and characterized by serious cognitive deficits and functional impairment. In the present systematic review, we address with a direct and reverse translational perspective the efficacy of D-amino acids, including D-serine, D-aspartate, and D-alanine, in poor responders. The impact of these molecules on the synaptic architecture is also considered in the light of dendritic spine changes reported in schizophrenia and antipsychotics’ effect on postsynaptic density proteins. Moreover, we describe compounds targeting D-amino acid oxidase and D-aspartate oxidase enzymes. Finally, other drugs acting at NMDAR and proxy of D-amino acids function, such as D-cycloserine, sarcosine, and glycine, are considered in the light of the clinical burden of TRS, together with other emerging molecules.

Fiber-specific overexpression of GhACO1 driven by E6 promoter improves cotton fiber quality and yield

Cotton (Gossypium hirsutum) is the most important fiber crop globally and there is an incentive to improve cotton fiber yield and quality to meet the growing market demand. 1-Aminocyclopropane-1-Carboxylic Acid Oxidase (ACO) has been identified as a rate-limiting enzyme in the biosynthesis of ethylene that is known to play a pivotal regulatory role in fiber development. According to transcriptomic data analysis, GhACO1 is preferentially expressed at fiber elongation stage in a number of G. hirsutum varieties, suggestive of its involvement in regulating fiber development. Ethylene is known to cause premature senescence, and to abrogate its potential negative effects on plant growth by constitutive overexpression of GhACO1, a fiber-specific promoter E6 that imparts strong transcriptional activity in fiber elongation stage was employed to drive GhACO1 expression to improve fiber quality. The E6::GhACO1 cotton transgenic lines showed substantial improvements in fiber length, fiber strength and fiber yield relative to wild type. Exogenous application of pyrazinecarboxylic acid that is an effective inhibitor of ACO enzyme inhibited fiber elongation in ovule culture, validating that GhACOs may improve fiber quality by increasing ethylene levels. Furthermore, RNA-Seq analysis showed that upregulation of GhACO1 can activate the transcription of genes that are involved in hydrogen peroxide metabolism, cell wall loosening and cytoskeleton arrangement, thereby promoting fiber elongation. These findings suggest that GhACO1 is a key regulator of fiber development, and the application of “E6::GhACO1” strategy breaks the negative correlation between fiber quality and fiber yield, providing a novel route in formulating fiber improvement strategies in cotton.

Pt Nanoparticles with Enhanced Deaminase‐like Activity: Example of Oxidative Deamination of 5‐Hydroxymethylfurfurylamine and Glutamic Acid

AbstractOxidative deamination is part of the metabolic pathways of amino acid oxidase and glutamate dehydrogenase enzymes, and enables obtaining α‐keto acid from amino compound with ammonia as a by‐product. This work presents the utilization of Pt‐based catalyst composed of small platinum nanoparticles supported on industrial silica support (Pt/SiO2). This nanozyme was tested in the oxidative deamination reaction of two amino compounds: 5‐hydroxymethylfurfurylamine (HMFA) to 5‐hydroxymethylfurfural (HMF) and glutamic acid (GA) to α‐ketoglutaric acid (KGA). This paper outlines the use of Pt nanozymes with deaminase‐like activity. We showed the ability of this nanozymes to be selective and active in liquid phase oxidative deamination of HMFA and glutamic acid in a 6 to 9 pH range at 60 °C under atmospheric pressure. Pt/SiO2 nanozyme actually plays as a deaminase mimic with high HMFA conversion (60%) and cumulative yield to the corresponding desaminated keto compounds (67%).

Antagonistic Roles of Gallates and Ascorbic Acid in Pyomelanin Biosynthesis of Pseudomonas aeruginosa Biofilms

Primarily synthesized for chelating metal ions from the surrounding media, the pyomelanin plays an important role in bacterial virulence where it is needed for infection and biofilm formation as well as protection from host immune response. In this study, two out of three phenolic acids, gallic acid, and propyl gallate induced pyomelanin in two clinical isolates of Pseudomonas aeruginosa and inhibited biofilm formation. Ascorbic acid treatment reversed the gallic acid and propyl gallate mediated pyomelanin synthesis without reversing the inhibition of the biofilm formation. mRNA expression study revealed the upregulation of homogentisic acid oxidase enzyme by ascorbic acid treatment, possibly contributing towards the inhibition of pyomelanin synthesis. Tannic acid did not show any antibacterial or pyomelanin-induction activities. The synergistic effect of gallates and ascorbic acid in the inhibition of biofilm formation and associated pyomelanin synthesis was evidenced which needs further studies to establish their antibacterial efficacies, especially against the clinical isolates of Pseudomonas sp.

Enhancing Electrochemical Biosensor Selectivity with Engineered d-Amino Acid Oxidase Enzymes for d-Serine and d-Alanine Quantification.

d-Amino acid oxidase (DAAO) enzymes bind a range of d-amino acids with variable affinity. As such, the design of selective DAAO-based enzymatic biosensors remains a challenge for real-world biosensor application. Herein, a methodology for developing biosensors with varying substrate selectivity is presented. First, we address DAAO-based biosensor selectivity toward d-serine by introducing point mutations into DAAO using rational design. Next, the wild-type yeast DAAO (RgDAAO WT) and variants human DAAO W209R and yeast M213G are characterized for their selectivity and activity toward d-serine and d-alanine, the preferred DAAO substrates. The DAAO enzymes have been immobilized for final biosensor design, where they demonstrate selectivity comparable to free DAAO. The cross-linking procedure impacts on DAAO structure and function and the use of a regeneration strategy allows the biosensor response to be improved.

Ochronotic Knee Arthropathy: A rare cause of arthritic knee pain and literature review of surgical considerations during knee arthroplasty

Ochronotic Knee Arthropathy: A rare cause of arthritic knee pain and literature review of surgical considerations during knee arthroplasty - IJOR- Print ISSN No: - 2581-8112 Online ISSN No:- 2581-9151 Article DOI No:- 10.18231/j.ijor.2020.021, IP International Journal of Orthopaedic Rheumatology-IP Int J Orthop Rheumat

Olgu Sunumu: Okronotik Artropati

Ochronosis is a rare metabolic disease caused by the deficiency of the homogentisic acid oxidase enzyme. It gives clinical findings related to the accumulation of homogentisic acid in soft tissues and excretion in urine. Patients with chronic arthropathy usually have some joint pain and inflammatory back pain. Although axial involvement radiologically resembles ankylosing spondylitis (AS), it is differentiated by the absence of typical syndesmophytes, facet involvement, sacroiliac erosion and fusion.Although there is no effective treatment for ochronosis disease; our patient was given a protein-poor diet, vitamin C supplementation (100 mg/kg/day) and analgesic treatment for symptoms recommended in the literature; and a reduction in joint complaints was observed. In this case, the aim is to diagnose the rare ochronotic arthropathy followed with the diagnosis of AS and to show that both axial and peripheral joint involvement can be together in this disease.

A case diagnosed of ochronosis after lombar dyscectomy

Ochronosis is the black discoloration of connective tissues seen with alkaptonuria, a metabolic disorder. Alkaptonuria is a rare autosomal recessive metabolic disorder caused by the lack of homogentisic acid oxidase enzyme. Alkaptonuria causes degenerative changes in cartilage, intervertebral disc and other tissues. The patients operated due to lumbar disc herniation in alkatonuria are very few. In this article a case of ochronosis in which the patient was determined after lumbar discectomy is presented.

Topical Hydroquinone use leading to Endogenous Ochronosis: A Case Report

Ochronosis is a rare disease characterized by skin pigment changes and degenerative arthritis caused by deposition of homogentisic acid in joint cartilage. There are exogenous and endogenous forms of the disease with the endogenous form typically caused by alkaptonuria, or a defect in homogentisic acid oxidase enzyme. In this report we present a previously undocumented case of endogenous ochronosis caused by topical hydroquinone use in a 69-year-old Caucasian male without alkaptonuria.

Alkaptonuria—an atypical case: multi-modality imaging review

Alkaptonuria is a rare inborn metabolic disorder due to a mutation in the homogentisic acid oxidase enzyme (HGO) gene on chromosome 3q. As HGO is deficient in alkaptonuria patients, there is an accumulation of homogentisic acid in the blood and urine. Homogentisic acid gets deposited in the soft tissues, tendons, cartilages, large joints and intervertebral discs. Ochronosis usually affects the dorsolumbar spine and typically spares the cervical spine and sacroiliac joints. However, in this case of isolated ochronosis, we report co-existent extensive cervical spine degenerative changes and cervical vertebral fusion, which has not been described in the literature so far.

English

The effects of microwave (MW) dry blanching of mango in comparison with conventional water blanching and blanching in closed plastic bags prior to hot air drying (70&deg;C) were evaluated on the retention of vitamin C and &beta;-carotene and on the activity of polyphenol oxidase (PPO) and ascorbic acid oxidase (AAO) enzymes. Blanching conditions for MW and water blanching were 2 min at 90&deg;C high temperature and short time (HTST) or for 10 min at 70&deg;C low temperature and low time (LTLT). PPO was completely inactivated by the blanching treatments, while low AAO activity remained. High retentions (~100%) of vitamin C were found in dried mango after blanching treatments HTST with MW and blanching in closed plastic bags, while lower retention was observed after LTLT with MW (81.8 &plusmn; 4.5%), and conventional water blanching 86.7 &plusmn; 2.6% (HTST) and 78.6 &plusmn; 2.5% (LTLT). Blanching resulted in partial oxidation of L-AA into dehydroascorbic acid (DHAA). Lower retention of all-trans-&beta;-carotene was obtained in MW and HTST water blanched dried mango (82 to 90%) compared with LTLT water blanched dried mango (~100%). In all dried blanched mango samples the levels of 13-cis-&beta;-carotene isomer increased. A slight darkening of colour was observed only in conventional blanched mango samples. &nbsp; Key words: Microwave heating, mango, &beta;-carotene, vitamin C, ascorbic acid oxidase.

A case of exogenous ochronosis associated with hydroxychloroquine.

Exogenous ochronosis is characterized by hyperpigmented skin lesions that arise in association with local suppression of homogentisic acid oxidase enzyme. Although it generally develops in association with topical application of chemical agents, it can occasionally develop in association with antimalarial drugs. Here we present the case of a patient with rheumatoid arthritis who developed hyperpigmentation on the face and neck regions during hydroxychloroquine treatment. Hydroxychloroquine is being widely used in rheumatology practice, and cutaneous hyperpigmentation may develop as an adverse effect. In the present case, we emphasize the potential underlying mechanisms through which it may cause cutaneous hyperpigmentation and determine the clinical and histopathological findings of exogenous ochronosis.

L-Amino acid oxidase from Cerastes vipera snake venom: Isolation, characterization and biological effects on bacteria and tumor cell lines

A homodimeric l-amino acid oxidase enzyme (Cv-LAAOI) was isolated from the venom of Cerastes vipera (Egyptian Sand viper) using gel filtration followed by anion exchange chromatography. The molecular mass of Cv-LAAO is 120 kDa in its native form and 60 kDa in its monomeric form. The optimum enzyme activity was achieved on l-Leucine as a substrate in 50 mM buffer pH 7.5 at 50 °C. The Cv-LAAOI activity was significantly reduced by increasing the temperature over 40 °C, lost 75% of its activity at 60 °C and inhibited completely at 80 °C. The Cv-LAAOI attains the highest substrate specificity towards L-Met. The results have also indicated that Mn2+ enhances the enzyme activity by 10%, while Cu2+, Hg2+, Ni2+, Co2+ have suppressive effects on the Cv-LAAOI activity. On the other hand, EDTA has no significant effect on the enzyme activity. The kinetic parameters of Cv-LAAOI activity (Km, Kcat and Vmax) estimated on l-Leucine at pH 8 and 37 °C were found to be 2 mM, 12 S−1 and 16.7 μmol/min/ml, respectively. In addition, the results have shown that Cv-LAAOI exhibits a significant bactericidal activity against gram-positive and gram-negative bacteria, particularly Staphylococcus aureus and Escherichia coli with MIC values of 20 μg/ml. Moreover, Cv-LAAOI has exhibited a considerable cytotoxic activity against breast cancer cell line (MCF-7) with IC50 value 2.75 ± 0.38 μg/ml compared with different tumor cell lines (liver HepG2, lung A549, colon HCT116 and prostate PC3). Furthermore, Cv-LAAOI has triggered antiproliferative activity via extensive H2O2 generation as indicated by the increase in H2O2 and TBARS levels accompanied by the depletion in the catalase activity (CAT) in MCF-7 treated cells compared to the untreated ones. Thus, these findings clearly indicate that Cv-LAAOI has a selective cytotoxic effect on breast cancer cell line, demonstrating a great prospective for future use in cancer therapy.

Effect of Vaccinium macrocarpon on MK-801-induced psychosis in mice.

OBJECTIVES:This study was aimed to investigate the effect of aqueous cranberry extract (ACE) on MK-801-induced psychosis in mice.MATERIALS AND METHODS:MK-801-treated mice were administered ACE (1 and 2 g/kg, p.o.) for 14 days. Various behavioral parameters and neurochemical estimations such as dopamine (DA), 5-hydroxytryptamine (5-HT), norepinephrine (NE), gamma-aminobutyric acid (GABA), glutamate, and glycine as well as markers of oxidative stress such as nitrite levels were measured.RESULTS:Psychosis-induced mice showed a significant elevation of immobility time in forced swim test, locomotor activity, and reduction in time of permanency in rota-rod test, escape latency time in Cook's pole test while treatment with ACE showed a significant alteration in above-mentioned behavioral parameters in MK-801-induced psychosis. Moreover, MK-801-induced psychosis in the mice showed a significant increase in DA, 5-HT, and NA levels and decrease in GABA, glutamate, and glycine levels in the brain. In contrast, treatment with ACE at both doses remarkably altered the neurochemical parameters. In addition, ACE-treated mice showed a substantial reduction in acetylcholinesterase, D-amino acid oxidase enzyme activity, and nitrite levels which were elevated by the administration of MK-801.CONCLUSIONS:Treatment with ACE once for 14 days (1 and 2 g/kg) significantly ameliorated the behavioral symptoms in experimentally induced psychosis by virtue of neuromodulation and decreased oxidative stress.

ETHANOL AND NITRIC OXIDE IN QUALITY MAINTENANCE OF ‘GALAXY’ APPLES STORED UNDER CONTROLLED ATMOSPHERE

ABSTRACT The aim of this work was to evaluate the effect of ethanol and two nitric oxide dose applications on the maintenance of the post-storage quality of ‘Galaxy’ apple during storage under controlled atmosphere (CA). Treatments evaluated were: [1] 1.2 kPa O2 + 2.0 kPa CO2; [2] CA + 20 µL L-1 of nitric oxide, [3] CA + 40 µL L-1 of nitric oxide; [4] CA + 1 ml of ethanol kg-1 fruit. Fruits received treatments before storage and were kept under CA during eight months and seven days of storage at 20 °C. Fruits had been kept on CA for eight months and seven days at 20° C. Fruits treated with ethanol showed higher ethylene production, low flesh firmness, high flesh breakdown, mealiness and acetaldehyde production. Fruits treated with 40 µL L-1 nitric oxide showed lower ethylene production, respiration rate and ACC oxidase ( (1-aminocyclopropane-1-carboxylic acid) oxidase enzyme activity. Apples treated with 20 uL L-1 nitric oxide showed higher ethylene production, respiration rate, internal ethylene concentration CO2 and ethanol concentration. Ethanol and nitric oxide application before storage have no benefits in maintaining fruit quality after storage under CA due to lower flesh firmness, higher mealiness incidence, flesh breakdown and decay incidence.