Effect of glutaminase 1 inhibitor on carbon tetrachloride-induced liver fibrosis in mice / 中国生物制品学杂志

@#Objective To investigate the effect of glutaminase 1(GLS1)specific inhibitor BPTES[bis-2-（5-phenylacetamido-1,3,4-thiadiazol-2-yl）ethyl sulfide]on the liver fibrosis in the mouse model of liver fibrosis induced by carbon tetrachloride(CCl4).Methods Male C57BL/6J mice were intraperitoneally injected with olive oil(control group),10%CCl4(10 μL/g,model group)or 10% CCl4(10 μL/g)+ BPTES(10 mg/kg,treatment group),with 10 mice in each group,two doses a week for four weeks to establish liver fibrosis model. Collagen deposition in mouse liver tissue was observed by Sirius red staining. The expression levels of actin alpha 2(Acta2),collagen typeⅠalpha 1(Col1a1)GLS1 and GLS1 protein were detected by qRT-PCR and immunohistochemical staining.Results Compared with the control group,the liver tissue of mice in the model group was generally enlarged,the surface was not smooth and granular,and the ratio of liver mass to tibia length significantly increased(t = 2. 979,P < 0. 05);The Sirius red positive area of collagen deposition increased signifi-cantly in the liver tissue of mice in the model group(t = 7. 661,P < 0. 01),the relative expression levels of Acta2 and Col1a1 significantly increased(t = 4. 335 and 5. 319,respectively,each P < 0. 01),and the mRNA and protein levels of GLS1 significantly increased(t = 5. 319 and 9. 725,respectively,each P < 0. 01). However,compared with the model group,the BPTES treatment group had a reduction in liver mass,a significant reduction in the Sirius red positive area of collagen deposition in liver tissue(t = 7. 427,P < 0. 01),and a significant reduction in the relative expressions of Atca2 and Col1a1(t = 3. 713 and 2. 628,respectively,each P < 0. 05).Conclusion Inhibition of GLS1activity can significantly improve the degree of liver fibrosis induced by CCl4,providing a new idea for the treatment of liver fibrosis.

Research Progress in Improving Efficacy of Radiotherapy by Targeting Glutamine Metabolism / 肿瘤防治研究

Radiotherapy is an important treatment method for malignant tumors. Radiation resistance is the main obstacle to the therapeutic effect of radiotherapy. Cellular metabolic reprogramming is one of the main features of cancer, and it may have an important effect on the therapeutic effect of radiotherapy. Glutamine is closely related to tumor cell biosynthesis and growth. It affects radiotherapy sensitivity by producing antioxidants through decomposition. In addition, the expression patterns and functions of two isoenzymes of glutamine, namely, glutaminase (GLS) and glutaminase 2 (GLS2), are different and have an important influence on the sensitivity of radiotherapy. The utilization of glutamine metabolism in the tumor microenvironment has great research value to improve the efficacy of radiotherapy. This review describes the metabolic characteristics of glutamine in malignant tumors and the sensitization effect of glutamine inhibitors on the efficacy of radiotherapy.

Inhibition of liver glutaminase activity by Diallyl disulfide in experimentally induced hepatoma in mice

Background: Cancer cells addiction to glutamine, an essential non-essential amino acid, has stirred up the interest in researchers across the globe. Increased glutamine metabolism (glutaminolysis) is a hallmark of cancer. Targeting glutaminolysis via glutaminase inhibition emerges as a promising strategy to disrupt cancer metabolism and tumor progression. Diallyl disulfide (DADS), a major organosulfur compound derived from garlic, is known for its anticancer properties. The mechanisms of action of DADS include activation of metabolic enzymes that detoxify carcinogens, suppression of the formation of DNA adducts, antioxidant effects, regulation of cell-cycle progression, induction of apoptosis, and inhibition of angiogenesis and metastasis. Aim: to assess the effect of diallyl disulfide on liver glutaminase activity in experimentally induced hepatoma in mice. Materials & Methods: Swiss albino male mice were divided into four groups - normal, control, preventive and curative groups. Hepatoma was induced by intraperitoneal injection of Ehrlich ascites carcinoma (EAC) cells. DADS (100 mg/kg body weight/mouse/day) was orally fed to protective and curative group mice for a stipulated time period. Mice of all the groups were sacrificed, and liver tissue glutaminase activity were measured. Results: The present study shows a significant decrease in glutaminase activity in protective (p >0.001) and curative groups (p >0.001) as compared to control group. Conclusion: DADS at the dosage employed shows inhibitory effects on liver glutaminase activity which may be attributed to anti-inflammatory properties of DADS, specifically in suppression of NF-kB signalling pathway.

Validation of compound C19 as a glutaminase C inhibitor / 药学学报

The mitochondrial enzyme glutaminase C (GAC) is highly expressed in a variety of cancer cells, resulting in increased glutamine metabolism and cancer development. Therefore, GAC has become a potential target for anti-tumor drug development. However, current GAC inhibitors shared similar structural characteristics, few new scaffolds were reported. By conducting a prokaryotic Escherichia coli expression system, human GAC protein of high-purity was obtained through lysozyme digestion combined with ultrasound dissociation, and cobalt magnetic beads purification, Moreover, we performed studies to validate interaction between small molecules and GAC protein through thermal shift assay, drug affinity responsive target stability assay, protein crosslinking and GAC enzyme activity detection. Meanwhile, a comprehensive small molecule-protein interaction confirmation and systematic pharmacodynamic study in vitro were carried out on compound C19, which was a reported GAC inhibitor screened from the Enamine database. Results showed that C19 directly bind to GAC protein, disturbed GAC tetramers formation, and inhibited its enzyme catalytic activity. By interfering GAC function, C19 dose-dependently suppressed GAC-mediated glutamine metabolism, reduced glutamate in cancer cells, and thus alleviated A549 and NCI-H1299 non-small cell lung cancer cell growth. Together, C19 was identified as a lead compound, providing a new strategy for the structural design of drugs targeting GAC.

Progress in Research on Glutamine Metabolism in Energy Metabolism of Gastric Cancer / 胃肠病学

Gastric cancer is one of the most common malignant tumors of digestive system. Due to lack of early diagnosis methods, the mortality rate of gastric cancer is relatively high. For meeting their own needs, the tumor cells can reprogram their metabolism, and glutamine metabolism plays an important role in tumor cell growth and proliferation. Therefore, it needs to elucidate the new potential molecular mechanisms of gastric cancer and to discover the potential biomarkers related to glutamine metabolism, so as to provide new targets and schemes for the diagnosis and treatment of gastric cancer. This article reviewed the progress in research on glutamine metabolism in energy metabolism of gastric cancer.

Inhibiting silence information regulator 2 and glutaminase in the amygdala can improve social behavior in autistic rats / 浙江大学学报·医学版

OBJECTIVE@#To investigate the underlying molecular mechanisms by which silence information regulator (SIRT) 2 and glutaminase (GLS) in the amygdala regulate social behaviors in autistic rats.@*METHODS@#Rat models of autism were established by maternal sodium valproic acid (VPA) exposure in wild-type rats and SIRT2-knockout ( SIRT2 -/-) rats. Glutamate (Glu) content, brain weight, and expression levels of SIRT2, GLS proteins and apoptosis-associated proteins in rat amygdala at different developmental stages were examined, and the social behaviors of VPA rats were assessed by a three-chamber test. Then, lentiviral overexpression or interference vectors of GLS were injected into the amygdala of VPA rats. Brain weight, Glu content and expression level of GLS protein were measured, and the social behaviors assessed.@*RESULTS@#Brain weight, amygdala Glu content and the levels of SIRT2, GLS protein and pro-apoptotic protein caspase-3 in the amygdala were increased in VPA rats, while the level of anti-apoptotic protein Bcl-2 was decreased (all P<0.01). Compared with the wild-type rats, SIRT2 -/- rats displayed decreased expression of SIRT2 and GLS proteins in the amygdala, reduced Glu content, and improved social dysfunction (all P<0.01). Overexpression of GLS increased brain weight and Glu content, and aggravated social dysfunction in VPA rats (all P<0.01). Knockdown of GLS decreased brain weight and Glu content, and improved social dysfunction in VPA rats (all P<0.01).@*CONCLUSIONS@#The glutamate circulatory system in the amygdala of VPA induced autistic rats is abnormal. This is associated with the upregulation of SIRT2 expression and its induced increase of GLS production; knocking out SIRT2 gene or inhibiting the expression of GLS is helpful in maintaining the balanced glutamate cycle and in improving the social behavior disorder of rats.

Advances in antitumor drugs based on glutamine metabolism / 中国临床药理学与治疗学

Glutamine, as a conditionally essential amino acid of many kinds of tumors, has a great influence on the occurrence and development of tumors. In recent years, the research on glutamine metabolism has made rapid progress, and many related drugs have been in preclinical and clinical research. Glutamine is involved in energy generation, redox balance, macromolecular synthesis and signal transmission in tumor cells. Transporters and metabolic enzymes of glutamine are potential targets for tumor treatment. This paper reviews the anti-tumor drugs based on glutamine metabolism and provides guidance for the development of new drugs.

Enhanced production of glutaminase-free L-asparaginase by marine Bacillus velezensis and cytotoxic activity against breast cancer cell lines

Background: The increasing rate of breast cancer globally requires extraordinary efforts to discover new effective sources of chemotherapy with fewer side effects. Glutaminase-free L-asparaginase is a vital chemotherapeutic agent for various tumor malignancies. Microorganisms from extreme sources, such as marine bacteria, might have high L-asparaginase productivity and efficiency with exceptional antitumor action toward breast cancer cell lines. Results: L-Asparaginase-producing bacteria, Bacillus velezensis isolated from marine sediments, were identified by 16S rRNA sequencing. L-Asparaginase production by immobilized cells was 61.04% higher than that by free cells fermentation. The significant productivity of enzyme occurred at 72 h, pH 6.5, 37°C, 100 rpm. Optimum carbon and nitrogen sources for enzyme production were glucose and NH4Cl, respectively. L-Asparaginase was free from glutaminase activity, which was crucial medically in terms of their severe side effects. The molecular weight of the purified enzyme is 39.7 KDa by SDS-PAGE analysis and was ideally active at pH 7.5 and 37°C. Notwithstanding, the highest stability of the enzyme was found at pH 8.5 and 70°C for 1 h. The enzyme kinetic parameters displayed Vmax at 41.49 µmol/mL/min and a Km of 3.6 × 10−5 M, which serve as a proof of the affinity to its substrate. The anticancer activity of the enzyme against breast adenocarcinoma cell lines demonstrated significant activity toward MDA-MB-231 cells when compared with MCF-7 cells with IC50 values of 12.6 ± 1.2 µg/mL and 17.3 ± 2.8 µg/mL, respectively. Conclusion: This study provides the first potential of glutaminase-free L-asparaginase production from the marine bacterium Bacillus velezensis as a prospect anticancer pharmaceutical agent for two different breast cancer cell lines.

Twin-arginine signal peptide of Bacillus licheniformis GlmU efficiently mediated secretory expression of protein glutaminase

Background: Protein glutaminase specifically deamidates glutamine residue in protein and therefore significantly improves protein solubility and colloidal stability of protein solution. In order to improve its preparation efficiency, we exploited the possibility for its secretory expression mediated by twin-arginine translocation (Tat) pathway in Bacillus licheniformis. Results: The B. licheniformis genome-wide twin-arginine signal peptides were analyzed. Of which, eleven candidates were cloned for construction of expression vectors to mediate the expression of Chryseobacterium proteolyticum protein glutaminase (PGA). The signal peptide of GlmU was confirmed that it significantly mediated PGA secretion into media with the maximum activity of 0.16 U/ml in Bacillus subtilis WB600. A mutant GlmU-R, being replaced the third residue aspartic acid of GlmU twin-arginine signal peptide with arginine by site-directed mutagenesis, mediated the improved secretion of PGA with about 40% increased (0.23 U/ml). In B. licheniformis CBBD302, GlmU-R mediated PGA expression in active form with the maximum yield of 6.8 U/ml in a 25-l bioreactor. Conclusions: PGA can be produced and secreted efficiently in active form via Tat pathway of B. licheniformis, an alternative expression system for the industrial-scale production of PGA.

The Association of Glutaminase (glut) P3 Different Alleles of Trichomonas vaginalis with Infertility in a sample of Iraqi women

Trichomonas vaginalis (T. vaginalis), the etiologic agent of human trichomoniasis, is a flagellated protozoan parasite, has been associated sith advese pregnancy outcomes, HIV transmission, and infertilityh. A total of one hundred and fifty-seven (157) women at childbearing age (14-49 years), were included in the presnt study, eighty six (86) symptomatic fertile while the other seventy-one (71) were infertile with or without sumptoms attending the Gynecology outpatient Department in Al-Emamayn Al-Kadhimayn Medical City, the High Institute of Infertility Diagnosis and Assisted Reproductive Technoligies at Al-Nahrain University in Baghdad, the maternity Teaching hospital, and Dr. Khawer center for infertility and IVF in Erbil province in Iraq. Two vaginal swab specimens were obtained from each of them:; one swab was immediately examined by wet mount microscopy, the other swab for molecular study (DNA extraction and p3 nested PCR). One hundred (100) samples positive in one or more test were identified: 20 (12.7%) infecions were detected by wet mount microscopy, while nested PCR was positive in 100 (63.7%) samples. These positive samples were seguenced and phylogenetic tree were done and, there was no association between the variations in glut (p3) gene of T. vaginalis isolated from infected women (fertile and infertile)

Response to gluten free diet in sero-positive celiac disease children suffering from severe acute malnutrition in age group 1-5 years

Background: Diagnosis of celiac disease in children suffering from severe acute malnutrition without duodenal biopsy or HLA typing is a dilemma. The objective of this study was to study the response to gluten free diet in sero-positive Celiac Disease children suffering from severe acute malnutrition in age group 1-5 years.Methods: This prospective, observational, hospital-based study was conducted at MTC of tertiary care medical college hospital of southern Rajasthan from Dec. 2017 to Nov. 2018. Total 110 children with SAM were enrolled and screened for celiac disease on the basis of tissue tTg-IgA/IgG serology. Seropositive cases were kept on gluten free diet for short period of time and observed for the resolution of symptoms and improvement in growth, monitored by anthropometry on discharge and follow up visit.Results: Mean weight gain (gm/kg/day) on follow up was 3.87'3.49 in seropositive and 1.88'3.79 in seronegative cases (P-value<0.05). Mean weight gain was 6.43'3.28gm/kg/day in only tTg-IgA positive and 3.04'2.95 gm/kg/day in only tTg-IgG positive cases (P-value-<0.05). The mean weight gain in strictly gluten free adherent sero-positive cases was 4.89'2.97 gm/kg/day while in gluten free non-adherent patients it was -0.49'1.70 (P-value <0.001). Mean weight gain in probable (tTg-Ig-A <10 times ULN) and presumptive (tTg-IgA >10 times ULN) Celiac disease were 3.44'3.73 and 5.44'3.78, respectively without statically significant difference (P-value >0.05).Conclusions: In situations where facility of duodenal biopsy and or HLA DQ2/DQ8 typing is not available, resolution of symptoms and improvement in growth on gluten free diet confirms the diagnosis of celiac disease.

Research progress on the novel glutaminase inhibitor and its antitumor activity / 中国肿瘤临床

Tumor cells use several metabolic pathways to support bioenergetic and biosynthetic demands of proliferation. In addition to glucose, glutamine is an important source of precursor substances and energy for cancer cell growth. Glutaminase (GSL) activity is associated with Ras, c-Myc, and other oncogenes, as well as Rho GTP enzyme. Many preclinical studies have confirmed that glutamin-ase inhibitors not only exhibit anti-tumor activity, but can also remarkably enhance the sensitivity of resistant cancer cells to targeted drugs. At present, the novel GSL inhibitor CB-839 has entered phase I clinical trials and is expected to become a new drug for cancer treatment. This paper reviews the research progress on this novel glutaminase inhibitor and its antitumor activity.

Glutamine 1 regulates the chemosensitivity of intrahepatic cholangiocarcinoma cells to 5-FU by targeting major vault protein / 中华普通外科杂志

Objective To study the functions and mechanisms of glutamine 1 (GLS1) in intrahepatic cholangiocarcinoma (ICC) cell to 5-fluorouraeil (5-FU) chemosensitivity.Methods The expression and relation between GLS1 and major vault protein (MVP) in cholangiocarcinoma were analyzed by bioinformatics database.Western blot and immunohistochemistry were used to detect the expression of GLS1 and MVP in 42 ICC tissues,and the correlation between GLS1 and MVP was studied by statistics.The regulation of GLS1 in ICC cell were evaluated by siRNA interference and pcDNA overexpression,and then tested the interference and overexpression efficiency of GLS1 by Western blotting.The chemosensitivity to 5-Fu was tested by cell counting kit-8 (CCK-8).Results The expression of GLS1 and MVP in ICC tissues was significantly up-regulated (tGLSI =3.963;tMVP =3.131,P ＜ 0.05),and the expression of GLS1 was positively correlated with MVP(r2 =0.351 7,P ＜ 0.05).Knockdown of GLS1 in QBC939 cells enhanced chemosensitivity of QBC939 cells to 5-Fu and notably downregulated MVP expression,while enforced expression of GLS1 in RBE cells promoted MVP expression and reduce cell sensitivity to 5-fluorouracil chemosensitivity.Conclusions GLS1 regulates the chemosensitivity of ICC cells to 5-Fu,and its mechanism may relates to the regulation of MVP.

Research progress on glutaminase / 中华肝胆外科杂志

Metabolism is the necessary process for cell growth and survival,and it is dramatically altered in cancer cells compared with that in normal cells,and these alterations are known as the Warburg effect.Glutamine plays a decisive role in the metabolic processes.And the glutaminase as a enzyme in the processes has also become a hot topic of research in recent years.This article could focus on the recent research progress on glutaminase.

Isolation and identification of actinomycetes for production of novel extracellular glutaminase free L-asparaginase.

Over the recent years glutaminase free L-asparaginase has gained more importance due to better therapeutic properties for treatment of acute lymphoblastic leukemia. Actinomycetes are known for L-asparaginase activity. In the current study, 80 actinomycetes were isolated from various soil habitats by serial dilution technique. Presence of L-asparaginase was investigated in a total of 240 actinomycetes by tubed agar method using modified M-9 medium. A total of 165 actinomycetes were found positive for L-asparaginase activity. Among these, 57 actinomycetes producing larger zones of L-asparagine hydrolysis were further screened for their capacity to produce glutaminase-free L-asparaginase. Four L-glutaminase-free actinomycetes were found to be potential L-asparaginase producers. These actinomycetes were identified as Streptomyces cyaneus (SAP 1287, CFS 1560), S. exfoliates (CFS 1557) and S. phaeochromogenes (GS 1573) on the basis of morphological and biochemical identification studies. Maximum L-asparaginase activity (19.2 Uml-1) was observed in culture filtrate of S. phaeochromogenes under submerged fermentation. Results indicate that S. phaeochromogenes could be a potential source of glutaminase free L-asparaginase for commercial purpose. To the best of our knowledge, this is the first report on production of glutaminase free L-asparaginase from S. cyaneus, S. exfoliatus and S. phaeochromogenes.

Production, purification and characterization of L-Glutaminase from Streptomyces sp. isolated from soil.

L-Glutaminase, an amidohydrolase enzyme has been a choice of interest in the treatment of lymphoblastic leukaemia. The present study reports production, purification and characterization of extracellular glutaminase enzyme from Actinomycetes. Screening was performed for twenty Actinomycetes isolates from soil; one isolate (Isolate 2) was finally selected based on the activity of glutaminase (32.5 U/ml).The isolate was identified as Streptomyces sp. Effect of physicochemical factors namely temperature, pH, NaCl concentration, and supplementary carbon & nitrogen sources on the production of L-glutaminase from the Streptomyces sp. was carried out. The enzyme production was found to be optimum with glucose as carbon source (33 U/ml), L-glutamine as nitrogen source (33.1 U/ml), at 7 pH (32.8 U/ml), temperature 30oC (32.4 U/ml) and for 0.1% NaCl concentration (32.5 U/ml). The L-glutaminase produced from Streptomyces sp. was purified by ammonium sulphate precipitation, dialysis method and ion exchange chromatography. After the purification of the enzyme by ion exchange chromatography, it has been purified 46-fold from cell-free extract and yield was 3.25%. Characterization of extracellular L-glutaminase showed that the enzyme shown optimal activity at temperature of 30°C, pH 7, at 2% NaCl and for 0.04M substrate and the Km value was calculated to be 2.8mM and Vmax was 7.57 U/ml. The molecular weight of enzyme as determined by sodium dodecyl sulphate polyacrylamide electrophoresis (SDS-PAGE) was found to be 50 kDa.

Enzyme Therapy: Current Perspectives.

Enzymes control all metabolic processes in human system from simple digestion of food to highly complex immune response. Physiological reactions occuring in healthy individuals are disturbed when enzymes are deficient or absent. Enzymes are administered for normalizing biological function in certain pathologies. Initially, crude proteolytic enzymes were used for the treatment of gastrointestinal disorders. Recent advances have enabled enzyme therapy as a promising tool in the treatment of cardiovascular, oncological and hereditary diseases. Now, a spectrum of other diseases are also covered under enzyme therapy. But, the available information on the use of enzymes as therapeutic agents for different diseases is scanty. This review details the enzymes which have been used to treat various diseases/disorders.

Kinetic properties of Streptomyces canarius L- Glutaminase and its anticancer efficiency

Abstract L-glutaminase was produced by Streptomyces canarius FR (KC460654) with an apparent molecular mass of 44 kDa. It has 17.9 purification fold with a final specific activity 132.2 U/mg proteins and 28% yield recovery. The purified L-glutaminase showed a maximal activity against L-glutamine when incubated at pH 8.0 at 40 °C for 30 min. It maintained its stability at wide range of pH from 5.0 11.0 and thermal stable up to 60 °C with Tm value 57.5 °C. It has high affinity and catalytic activity for L-glutamine (Km 0.129 mM, Vmax 2.02 U/mg/min), followed by L-asparagine and L-aspartic acid. In vivo, L-glutaminase showed no observed changes in liver; kidney functions; hematological parameters and slight effect on RBCs and level of platelets after 10 days of rabbit's injection. The anticancer activity of L-glutaminase was also tested against five types of human cancer cell lines using MTT assay in vitro. L-glutaminase has a significant efficiency against Hep-G2 cell (IC50, 6.8 μg/mL) and HeLa cells (IC50, 8.3 μg/mL), while the growth of MCF-7 cells was not affected. L-glutaminase has a moderate cytotoxic effect against HCT-116 cell (IC50, 64.7 μg/mL) and RAW 264.7 cell (IC50, 59.3 μg/mL).

Doença celíaca / Celiac disease

A doença celíaca (DC) é uma enteropatia caracterizada pela intolerância permanente ao glúten desencadeada por mecanismos autoimunes nos indivíduos geneticamente predispostos. A DC com seu quadro clínico típico e principalmente atípico tem se mostrado mais frequente do que se imaginava. Seu diagnóstico é baseado em suspeita clínica, exames sorológicos e biópsia intestinal. Devido à evolução dos marcadoressorológicos e revisão dos critérios diagnósticos, discute-se sobre a real necessidade da realização da biópsia intestinal em casos selecionados. O tratamento da DC continua sendo a dieta isenta de glúten.

Celiac disease (CD) is an enteropathy characterized by permanent intolerance to gluten triggered by autoimmune mechanisms in genetically predisposed individuals. The frequency of CD, with its typical clinical condition and mainly atypical, has been higher than expected. Its diagnosis is based on clinical suspicion, serologic tests, and intestinal biopsy. The evolution of the knowledge about serological markers and revision of thediagnostic criteria prompts questions about the real need of intestinal biopsy in selected cases. The treatment of CD remains the gluten-free diet.

Purification, Kinetic Properties and Antitumor Activity of L-Glutaminase from Penicillium brevicompactum NRC 829.

Aim: The aims of the present study were to purify and characterize L-glutaminase from Penicillium brevicompactum NRC 829; and to evaluate the antitumor activity of the purified enzyme against different tumor human cell lines. Study Design: Testing of antitumor activity of L-glutaminase, purified from a filamentous fungal strain, against four different tumor human cell lines. Place and Duration of Study: Department of Microbial Chemistry, Genetic Engineering and Biotechnology Division, National Research Centre (NRC), Cairo, Egypt, between January 2011 and February 2012. Methodology: P. brevicompactum NRC 829 was grown and maintained on modified Czapek Dox agar (MCD) medium. Cell-free extract was directly used as the source of crude enzyme. L-glutaminase was purified by heat treatment for 20 min at 50ºC, followed by gel filtration on Sephadex G-100 and G-200 columns. Results: An intracellular L-glutaminase from Penicillium brevicompactum NRC 829 was purified to homogeneity (162.75 fold) with an apparent molecular mass (Mr) of 71 kDa. The purified enzyme showed its maximal activity against L-glutamine when incubated at pH 8.5 at 50ºC for 30 min. The purified enzyme retained about 92 % of its initial activity after incubation at 70ºC for 30 min indicating the thermo-stability nature of this enzyme. The highest activity was reported towards its natural substrate, L-glutamine, with an apparent Km value of 1.66 mM. The purified enzyme inhibited the growth of human cell line hepatocellular carcinoma (Hep-G2), with IC50 value of 63.3μg/ml. Conclusion: L-glutaminase purified from Penicillium brevicompactum NRC 829 is a potential candidate in food and pharmaceutical industries.