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metabolism
the expression of At3g08860 is highly coordinated with the genes of the uracil degradation pathway leading to the non-proteinogenic amino acid beta-alanine
evolution
AGT is a homodimer and belongs to the fold type I family of PLP-dependent enzymes. Enzyme AGT is present in the human population in two allelic forms, the major allele encoding AGT-Ma and the minor allele encoding AGT-Mi, the latter characterized by the Pro11 to Leu and Ile340 to Met amino acid substitutions
evolution
AGT is homodimeric and belongs to the fold type I family of PLP-dependent enzymes
evolution
aminotransferase enzymes function via a bimolecular double displacement ping-pong mechanism where an amino acid usually serves as the amino donor and an alpha-keto acid serves as the amino acceptor. Aminotransferases are ubiquitous in the three domains of life and are involved in a variety of metabolic pathways including amino acid metabolism, nitrogen assimilation, gluconeogenesis, responses to a number of biotic/abiotic stresses, and among other pathways. The aminotransferase gene family in the model plant Arabidopsis thaliana consists of 44 genes, eight of which are suggested to be alanine aminotransferases. One of the putative alanine aminotransferases genes, At3g08860, is attributed the function of alanine:glyoxylate aminotransferase/beta-alanine:pyruvate aminotransferase based on the analysis of gene expression networks and homology to other beta-alanine aminotransferases in plants
evolution
enzyme AGT is present in the human population in two allelic forms, the major allele encoding AGT-Ma and the minor allele encoding AGT-Mi, the latter characterized by the Pro11 to Leu and Ile340 to Met amino acid substitutions
malfunction
alanine:glyoxylate aminotransferase deficiency causes primary hyperoxaluria type 1
malfunction
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causes the hereditary kidney stone disease primary hyperoxaluria type 1
malfunction
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deficiency is responsible for Primary Hyperoxaluria Type 1, an autosomal recessive disorder
malfunction
mutation W251K involved in primary hyperoxaluria type 1
malfunction
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primary hyperoxaluria type 1, a lethal inborn error of glyoxylate metabolism characterized by increased oxalate production, is caused by a deficiency of hepatic peroxisomal alanine:glyoxylate aminotransferase
malfunction
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The hereditary kidney stone disease primary hyperoxaluria type 1 is caused by a deficiency of the peroxisomal enzyme alanine:glyoxylate aminotransferase
malfunction
critical role of AGXT deletion during HCC progression, loss of AGXT expression is correlated with a poor prognosis and differentiation of HCC. Loss of AGXT expression promotes the malignant phenotypes of HCC cell lines
malfunction
deficit of AGT causes primary hyperoxaluria type I (PH1) (OMIM 259900), a rare metabolic recessive disease due to inborn errors affecting the metabolism of glyoxylate in liver peroxisomes. Molecular dynamics simulations of F152I-Mi and I244T-Mi variants associated with PH1 and implications in their pathogenicity
malfunction
deficit of AGT leads to primary hyperoxaluria type I (PH1), a rare disease characterized by calcium oxalate stones deposition in the urinary tract as a consequence of glyoxylate accumulation. Most missense mutations cause AGT misfolding, as in the case of the G41R, which induces aggregation and proteolytic degradation
malfunction
possible inverse correlation between the degree of destabilization/misfolding induced by a mutation and the extent of vitamin B6 responsiveness in PH1. Among the 79 missense mutations known to be associated with PH1, 26 involve residues directly located at the monomer-monomer interface
malfunction
primary hyperoxaluria type I (PH1) is a rare disease caused by mutations in the AGXT gene encoding alanine:glyoxylate aminotransferase (AGT), a liver enzyme involved in the detoxification of glyoxylate, the failure of which results in accumulation of oxalate and kidney stones formation. The role of protein misfolding in the AGT deficit caused by most PH1-causing mutations. Analysis of the clinical, biochemical and cellular effects of the p.Ile56Asn mutation, recently described in a PH1 patient, as a function of the residue at position 11, a hot-spot for both polymorphic (p.Pro11Leu) and pathogenic (p.Pro11Arg) mutations, overview. As compared with the non-pathogenic forms, AGT variants display reduced expression and activity in mammalian cells. Vitamin B6, a currently approved treatment for PH1, can overcome the effects of the p.Ile56Asn mutation only when it is associated with Pro at position 11. Primary hyperoxaluria type I (PH1), the most severe form of primary hyperoxaluria, is an inherited condition characterized by an increased endogenous production of oxalate, a metabolic end-product excreted by urine, that leads to the formation and precipitation of calcium oxalate crystals, first in the kidneys and urinary tract and then in many tissues including skin, bones, heart and retina, a condition known as systemic oxalosis
physiological function
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overexpression of human AGXT2 protects from asymmetric dimethylarginine-induced inhibition in nitric oxide production
physiological function
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indispensable for appressorium function
physiological function
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seems to be required for mobilization and utilization of triglycerides during infection process (to generate glycerol required for mechanical breaching of the host surface)
physiological function
alanine:glyoxylate aminotransferase (AGT) catalyzes the conversion of L-alanine and glyoxylate into pyruvate and glycine in liver peroxisomes, using pyridoxal 5'-phosphate (PLP) as coenzyme
physiological function
Arabidopsis thaliana alanine:glyoxylate aminotransferase 1 (AGT1) is a multifunctional class IV aminotransferase protein that catalyzes transamination reactions using L-serine, L-alanine, and L-asparagine as amino donors and glyoxylate, pyruvate, and hydroxypyruvate as amino acceptors. AGT1 is a peroxisomal aminotransferase with a central role in photorespiration. This enzyme catalyzes various aminotransferase reactions, including serine:glyoxylate, alanine:glyoxylate, and asparagine:glyoxylate transaminations
physiological function
primary hyperoxaluria type I (PH1) is a rare disease caused by the deficit of liver alanine-glyoxylate aminotransferase (AGT). AGT prevents oxalate formation by converting peroxisomal glyoxylate to glycine. When the enzyme is deficient, progressive calcium oxalate stones deposit first in the urinary tract and then at the systemic level. Pyridoxal 5'-phosphate (PLP), the AGT coenzyme, exerts a chaperone role by promoting dimerization
physiological function
role of AGXT in hepatocellular carcinoma (HCC) progression with effects of AGXT on cell cycle and apoptosis in HCC cells. The proportions of both early apoptotic and late apoptotic/necrotic cells increase as the expression of AGXT decreases
physiological function
the endogenous inhibitor of nitric oxide synthases asymmetric dimethylarginine (ADMA) can be catabolized by dimethylarginine dimethylaminohydrolase (DDAH, EC 3.5.3.18) or metabolized through an alternative pathway by alanine:glyoxylate aminotransferase 2 (AGXT2) with the formation of 2-oxo-D-(N,N-dimethylguanidino)valeric acid (ADGV). AGXT2 can metabolize the cardiovascular risk factors N-monomethylarginine (NMMA), asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA)
physiological function
the enzyme produces beta-alanine, which is an osmoprotectant in plants
physiological function
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the enzyme produces beta-alanine, which is an osmoprotectant in plants
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additional information
Arg118, Phe238 and Phe240 are interfacial residues not essential for transaminase activity but important for dimer-monomer dissociation. Molceular dynamics simulations
additional information
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Arg118, Phe238 and Phe240 are interfacial residues not essential for transaminase activity but important for dimer-monomer dissociation. Molceular dynamics simulations
additional information
in the enzyme crystal, another dimer related by noncrystallographic symmetry makes close interactions to form a tetramer mediated in part by an extra carboxyl-terminal helix conserved in plant homologues of AGT1. Residues Tyr35' and Arg36', entering the active site from the other subunits in the dimer, mediate interactions between AGT and L-serine when used as a substrate. Structural model of AGT1 and structure-function analysis, structure comparisons, detailed overview
additional information
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in the enzyme crystal, another dimer related by noncrystallographic symmetry makes close interactions to form a tetramer mediated in part by an extra carboxyl-terminal helix conserved in plant homologues of AGT1. Residues Tyr35' and Arg36', entering the active site from the other subunits in the dimer, mediate interactions between AGT and L-serine when used as a substrate. Structural model of AGT1 and structure-function analysis, structure comparisons, detailed overview
additional information
structural analysis and homology modeling of the At3g08860-encoded enzyme
additional information
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structural analysis and homology modeling of the At3g08860-encoded enzyme
additional information
the AGT catalytic mechanism is typical of PLP-dependent aminotransferases and comprises two half-reactions. In the first one, the alpha-amino group of the substrate L-alanine displaces the epsilon-amino group of Lys209 producing the external aldimine. Then, Lys209 acts as a general base for the 1,3-prototropic shift generating a ketimine intermediate, which hydrolyzes to pyruvate and pyridoxamine 5'-phosphate (PMP). In the second half-reaction, glyoxylate binds to AGT-PMP and, through the same steps of the first reaction but in a reverse order, is converted to glycine regenerating AGT-PLP
additional information
the overall transamination catalyzed by AGT follows a ping-pong mechanism