WorldWideScience

Sample records for aminohydrolases

  1. Purification and characterization of the enzymes involved in nicotinamide adenine dinucleotide degradation by Penicillium brevicompactum NRC 829

    OpenAIRE

    Ali, Thanaa Hamed; El-Ghonemy, Dina Helmy

    2016-01-01

    The present study was conducted to investigate a new pathway for the degradation of nicotinamide adenine dinucleotide (NAD) by Penicillium brevicompactum NRC 829 extracts. Enzymes involved in the hydrolysis of NAD, i.e. alkaline phosphatase, aminohydrolase and glycohydrolase were determined. Alkaline phosphatase was found to catalyse the sequential hydrolysis of two phosphate moieties of NAD molecule to nicotinamide riboside plus adenosine. Adenosine was then deaminated by aminohydrolase to i...

  2. Comparative study of adenosine deaminase activity, insulin resistance and lipoprotein(a) among smokers and healthy non-smokers

    OpenAIRE

    Ramesh Ramasamy; Sathish Babu Murugaiyan; Arulkumaran U.; Sathiya R.; Kuzhandai Velu V.; Niranjan Gopal

    2016-01-01

    Background: Adenosine deaminase also known as adenosine aminohydrolase involved in purine metabolism. Its primary function is development and maintenance of immune system. The main objective of the study was to estimate adenosine deaminase (ADA) enzyme and find its correlation with lipoprotein(a) and insulin resistance among smokers and healthy non-smokers. Methods: Fifty smokers and fifty healthy non-smokers were selected based on WHO definition. ADA, lipid profile and glucose was estimat...

  3. Directed evolution of an industrial N-acetyl-amino acid racemase

    OpenAIRE

    Baxter, Scott

    2013-01-01

    The use of stereoselective aminohydrolases (acylases) in kinetic resolutions is a commonly employed industrial route to both L- and D- α-amino acids from Nacetylated- DL-starting materials. However, a flaw in this process is the need for repeated racemisation steps of the non-desired enantiomer to achieve yields >50%. A solution to this drawback would be a dynamic kinetic resolution driven by an in situ racemisation step that would allow the yield to approach 100% A cheap and “...

  4. NCBI nr-aa BLAST: CBRC-RNOR-02-0090 [SEVENS

    Lifescience Database Archive (English)

    Full Text Available CBRC-RNOR-02-0090 ref|NP_071633.1| dimethylarginine dimethylaminohydrolase 1 [Rattu...s norvegicus] sp|O08557|DDAH1_RAT NG,NG-dimethylarginine dimethylaminohydrolase 1 (Dimethylargininase-1) (Dimethylarginine dimethyl...aminohydrolase 1) (DDAHI) (DDAH-1) dbj|BAA18993.1| N-G,N-G-dimethylarginine dimethyla...minohydrolase [Rattus norvegicus] gb|EDL82408.1| dimethylarginine dimethylaminohydrolase 1, isoform CRA_a [Rattus norvegicus] NP_071633.1 2e-20 56% ...

  5. Functional Analysis of the p40 and p75 Proteins from Lactobacillus casei BL23

    OpenAIRE

    Bäuerl, Christine; Pérez-Martínez, Gaspar; Yan, Fang; Polk, D. Brent; Monedero, Vicente

    2010-01-01

    The genomes of Lactobacillus casei/paracasei and Lactobacillus rhamnosus strains carry two genes encoding homologues of p40 and p75 from L. rhamnosus GG, two secreted proteins which display anti-apoptotic and cell protective effects on human intestinal epithelial cells. p40 and p75 carry cysteine, histidine-dependent aminohydrolase/peptidase (CHAP) and NLPC/P60 domains, respectively, which are characteristic of proteins with cell-wall hydrolase activity. In L. casei BL23 both proteins were se...

  6. Role of aminotransferases in glutamate metabolism of human erythrocytes

    Energy Technology Data Exchange (ETDEWEB)

    Ellinger, James J. [University of Wisconsin-Madison, Department of Biochemistry (United States); Lewis, Ian A. [Princeton University, Lewis-Sigler Institute for Integrative Genomics (United States); Markley, John L., E-mail: markley@nmrfam.wisc.edu [University of Wisconsin-Madison, Department of Biochemistry (United States)

    2011-04-15

    Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from {alpha}-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional {sup 1}H-{sup 13}C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis.

  7. The ygeW encoded protein from Escherichia coli is a knotted ancestral catabolic transcarbamylase

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yongdong; Jin, Zhongmin; Yu, Xiaolin; Allewell, Norma M.; Tuchman, Mendel; Shi, Dashuang (Maryland); (GWU); (Georgia)

    2012-06-28

    Purine degradation plays an essential role in nitrogen metabolism in most organisms. Uric acid is the final product of purine catabolism in humans, anthropoid apes, birds, uricotelic reptiles, and almost all insects. Elevated levels of uric acid in blood (hyperuricemia) cause human diseases such as gout, kidney stones, and renal failure. Although no enzyme has been identified that further degrades uric acid in humans, it can be oxidized to produce allantoin by free-radical attack. Indeed, elevated levels of allantoin are found in patients with rheumatoid arthritis, chronic lung disease, bacterial meningitis, and noninsulin-dependent diabetes mellitus. In other mammals, some insects and gastropods, uric acid is enzymatically degraded to the more soluble allantoin through the sequential action of three enzymes: urate oxidase, 5-hydroxyisourate (HIU) hydrolase and 2-oxo-4-hydroxy-4-carboxy-5-ureidoimidazoline (OHCU) decarboxylase. Therefore, an elective treatment for acute hyperuricemia is the administration of urate oxidase. Many organisms, including plants, some fungi and several bacteria, are able to catabolize allantoin to release nitrogen, carbon, and energy. In Arabidopsis thaliana and Eschrichia coli, S-allantoin has recently been shown to be degraded to glycolate and urea by four enzymes: allantoinase, allantoate amidohydrolase, ureidoglycine aminohydrolase, and ureidoglycolate amidohydrolase.

  8. Role of aminotransferases in glutamate metabolism of human erythrocytes

    International Nuclear Information System (INIS)

    Human erythrocytes require a continual supply of glutamate to support glutathione synthesis, but are unable to transport this amino acid across their cell membrane. Consequently, erythrocytes rely on de novo glutamate biosynthesis from α-ketoglutarate and glutamine to maintain intracellular levels of glutamate. Erythrocytic glutamate biosynthesis is catalyzed by three enzymes, alanine aminotransferase (ALT), aspartate aminotransferase (AST), and glutamine aminohydrolase (GA). Although the presence of these enzymes in RBCs has been well documented, the relative contributions of each pathway have not been established. Understanding the relative contributions of each biosynthetic pathway is critical for designing effective therapies for sickle cell disease, hemolytic anemia, pulmonary hypertension, and other glutathione-related disorders. In this study, we use multidimensional 1H–13C nuclear magnetic resonance (NMR) spectroscopy and multiple reaction mode mass spectrometry (MRM-MS) to measure the kinetics of de novo glutamate biosynthesis via AST, ALT, and GA in intact cells and RBC lysates. We show that up to 89% of the erythrocyte glutamate pool can be derived from ALT and that ALT-derived glutamate is subsequently used for glutathione synthesis.

  9. Isolation and characterization of human liver guanine deaminase.

    Science.gov (United States)

    Gupta, N K; Glantz, M D

    1985-01-01

    Guanine deaminase (EC 3.5.4.3, guanine aminohydrolase [GAH]) was purified 3248-fold from human liver to homogeneity with a specific activity of 21.5. A combination of ammonium sulfate fractionation, and DEAE-cellulose, hydroxylapatite, and affinity chromatography with guanine triphosphate ligand were used to purify the enzyme. The enzyme was a dimer protein of a molecular weight of 120,000 with each subunit of 59,000 as determined by gel filtration and sodium dodecyl sulfate-gel electrophoresis. Isoelectric focusing gave a pI of 4.76. It was found to be an acidic protein, as evidenced by the amino acid analysis, enriched with glutamate, aspartate, alanine and glycine. It showed a sharp pH optimum of 8.0. The apparent Km for guanine was determined to be 1.53 X 10(-5) M at pH 6.0 and 2 X 10(-4) M for 8-azaguanine as a substrate at pH 6.0. The enzyme was found to be sensitive to p-hydroxymercuribenzoate inhibition with a Ki of 1.53 X 10(-5) M and a Ki of 5 X 10(-5) M with 5-aminoimidazole-4-carboxamide as an inhibitor. The inhibition with iodoacetic acid showed only a 7% loss in the activity at 1 X 10(-4) M and a 24% loss at 1 X 10(-3) M after 30 min of incubation, whereas p-hydroxymercuribenzoate incubation for 30 min resulted in a 91% loss of activity at a concentration of 1 X 10(-4) M. Guanine was the substrate for all of the inhibition studies. The enzyme was observed to be stable up to 40 degrees C, with a loss of almost all activity at 65 degrees C with 30 min incubation. Two pKa values were obtained at 5.85 and 8.0. Analysis of the N-terminal amino acid proved to be valine while the C-terminal residue was identified as alanine. PMID:3966794