Publications

• Characterization of Arabidopsis serine:glyoxylate aminotransferase, AGT1, as an asparagine aminotransferase.

  Zhang Q., Lee J., Pandurangan S., Clarke M., Pajak A., Marsolais F.

  Asparagine (Asn) is a major form of nitrogen transported to sink tissues. Results from a previous study have shown that an Arabidopsis mutant lacking asparaginase activity develops relatively normally, highlighting a possible compensation by other types of asparagine metabolic enzymes. Prior studi ... >> More

  Asparagine (Asn) is a major form of nitrogen transported to sink tissues. Results from a previous study have shown that an Arabidopsis mutant lacking asparaginase activity develops relatively normally, highlighting a possible compensation by other types of asparagine metabolic enzymes. Prior studies with barley and tobacco mutants have associated Asn aminotransferase activity with the photorespiratory enzyme, serine (Ser):glyoxylate aminotransferase. This enzyme is encoded by AGT1 in Arabidopsis thaliana. Recombinant N-terminal His-tagged AGT1 purified from Escherichia coli was characterized with Ser, alanine (Ala) and Asn as amino acid donors and glyoxylate, pyruvate and hydroxypyruvate as organic acid acceptors. The V(max) of AGT1 with Asn was higher than with Ser or Ala by ca. 5-to 20-fold. As a result, the catalytic efficiency (V(max)/K(m)) was slightly higher with Asn than with the two other amino acids. In the roots of 10-day-old seedlings treated for 2h with 20mM Asn, the AGT1 transcript levels were raised by 2-fold. During this treatment, the concentration of Asn in root was raised by ca. 5-fold. These results suggest that AGT1 is involved in Asn metabolism in Arabidopsis. << Less

  Phytochemistry 85:30-35(2013) [PubMed] [EuropePMC]

  This publication is cited by 5 other entries.

• Isolation and characterization of an L-alanine: glyoxylate aminotransferase from human liver.

  Thompson J.S., Richardson K.E.

  J Biol Chem 242:3614-3619(1967) [PubMed] [EuropePMC]

• Characteristics of hepatic alanine-glyoxylate aminotransferase in different mammalian species.

  Noguchi T., Okuno E., Takada Y., Minatogawa Y., Okai K., Kido R.

  Mitochondrial extracts of dog, cat, rat and mouse liver contain two forms of alanine-glyoxylate aminotransferase (EC 2.6.1.44): one, designated isoenzyme 1, has mol.wt. approx. 80 000 and predominates in dog and cat liver; the other, designated isoenzyme 2, has mol.wt. approx. 175 000 and predomin ... >> More

  Mitochondrial extracts of dog, cat, rat and mouse liver contain two forms of alanine-glyoxylate aminotransferase (EC 2.6.1.44): one, designated isoenzyme 1, has mol.wt. approx. 80 000 and predominates in dog and cat liver; the other, designated isoenzyme 2, has mol.wt. approx. 175 000 and predominates in rat and mouse liver. In rat and mouse liver, isoenzyme 1 activity was increased by the injection in vivo of glucagon, but not isoenzyme 2 activity. Isoenzyme 1 was purified and characterized from liver mitochondrial extracts of the four species. Both rat and mouse enzyme preparations catalysed transamination between a number of L-amino acids and glyoxylate, and with L-alanine as amino donor the effective amino acceptors were glyoxylate, phenylpyruvate and hydroxypyruvate. In contrast, both dog and cat enzyme preparations were specific for L-alanine and L-serine with glyoxylate, and used glyoxylate and hydroxypyruvate as effective amino acceptors with L-alanine. Evidence that isoenzyme 1 is identical with serine-pyruvate aminotransferase (EC 2.6.1.51) was obtained. Isoenzyme 2 was partially purified from mitochondrial extracts of rat and mouse liver. Both enzyme preparations were specific for L-alanine and glyoxylate. On the basis of physical properties and substrate specificity, it was concluded that isoenzyme 2 is a separate enzyme. Some other properties of isoenzymes 1 and 2 are described. << Less

  Biochem J 169:113-122(1978) [PubMed] [EuropePMC]

• 3-Hydroxykynurenine transaminase identity with alanine glyoxylate transaminase. A probable detoxification protein in Aedes aegypti.

  Han Q., Fang J., Li J.

  This study describes the functional characterization of a specific mosquito transaminase responsible for catalyzing the transamination of 3-hydroxykynurenine (3-HK) to xanthurenic acid (XA). The enzyme was purified from Aedes aegypti larvae by ammonium sulfate fractionation, heat treatment, and va ... >> More

  This study describes the functional characterization of a specific mosquito transaminase responsible for catalyzing the transamination of 3-hydroxykynurenine (3-HK) to xanthurenic acid (XA). The enzyme was purified from Aedes aegypti larvae by ammonium sulfate fractionation, heat treatment, and various chromatographic techniques, plus non-denaturing electrophoresis. The purified transaminase has a relative molecular mass of 42,500 by SDS-PAGE. N-terminal and internal sequencing of the purified protein and its tryptic fragments resolved a partial N-terminal sequence of 19 amino acid residues and 3 partial internal peptide sequences with 7, 10, and 7 amino acid residues. Using degenerate primers based on the partial internal sequences for PCR amplification and cDNA library screening, a full-length cDNA clone with a 1,167-bp open reading frame was isolated. Its deduced amino acid sequence consists of 389 amino acid residues with a predicted molecular mass of 43,239 and shares 45-46% sequence identity with mammalian alanine glyoxylate transaminases. Northern analysis shows the active transcription of the enzyme in larvae and developing eggs. Substrate specificity analysis of this mosquito transaminase demonstrates that the enzyme is active with 3-HK, kynurenine, or alanine substrates. The enzyme has greater affinity and catalytic efficiency for 3-HK than for kynurenine and alanine. The biochemical characteristics of the enzyme in conjunction with the profiles of 3-HK transaminase activity and XA accumulation during mosquito development clearly point out its physiological function in the 3-HK to XA pathway. Our data suggest that the mosquito transaminase was evolved in a manner precisely reflecting the physiological requirement of detoxifying 3-HK produced in the tryptophan oxidation pathway in the mosquito. << Less

  J. Biol. Chem. 277:15781-15787(2002) [PubMed] [EuropePMC]

  This publication is cited by 9 other entries.

• Comparative characterization of Aedes 3-hydroxykynurenine transaminase/alanine glyoxylate transaminase and Drosophila serine pyruvate aminotransferase.

  Han Q., Li J.

  This study describes the comparative analysis of two insect recombinant aminotransferases, Aedes aegypti 3-hydroxykynurenine (3-HK) transaminase/alanine glyoxylate aminotransferase (Ae-HKT/AGT) and Drosophila melanogaster serine pyruvate aminotransferase (Dm-Spat), which share 52% identity in thei ... >> More

  This study describes the comparative analysis of two insect recombinant aminotransferases, Aedes aegypti 3-hydroxykynurenine (3-HK) transaminase/alanine glyoxylate aminotransferase (Ae-HKT/AGT) and Drosophila melanogaster serine pyruvate aminotransferase (Dm-Spat), which share 52% identity in their amino acid sequences. Both enzymes showed AGT activity. In addition, Ae-HKT/AGT is also able to catalyze the transamination of 3-HK or kynurenine with glyoxylate, pyruvate or oxaloacetate as the amino acceptor. Kinetic analysis and other data suggest that Ae-HKT/AGT plays a critical role in mosquito tryptophan catabolism by detoxifying 3-HK and that Dm-Spat is primarily involved in glyoxylate detoxification. << Less

  FEBS Lett. 527:199-204(2002) [PubMed] [EuropePMC]

• Dimethylarginine:pyruvate aminotransferase in rats. Purification, properties, and identity with alanine:glyoxylate aminotransferase 2.

  Ogawa T., Kimoto M., Sasaoka K.

  Dimethylarginine:pyruvate aminotransferase, which plays a role in the metabolism of dimethylarginines, has been purified to homogeneity from rat kidney. The enzyme has a molecular weight of approximately 200,000 and an isoelectric point at about pH 6.3. The enzyme consists of four similar subunits ... >> More

  Dimethylarginine:pyruvate aminotransferase, which plays a role in the metabolism of dimethylarginines, has been purified to homogeneity from rat kidney. The enzyme has a molecular weight of approximately 200,000 and an isoelectric point at about pH 6.3. The enzyme consists of four similar subunits having a molecular weight of about 50,000. The enzyme catalyzes the effective transaminations of guanidino-N methylated L-arginines (e.g. NG,NG-dimethyl-L-arginine, NG,N'G-dimethyl-L-arginine and NG-monomethyl-L-arginine) and the alpha-amino group of L-ornithine to pyruvate or glyoxylate. The enzyme was always accompanied by the known alanine:glyoxylate amino-transferase activity with the ratios of their specific activities remaining constant during the purification steps. The physicochemical and immunological properties of the purified enzyme were shown to be identical with those of the isozyme of alanine:glyoxylate aminotransferase (EC 2.6.1.44), designated as alanine:glyoxylate aminotransferase 2 (Noguchi, T. (1987) in Peroxisomes in Biology and Medicine (Fahimi, H. D., and Sies, H., eds) pp. 234-243, Springer-Verlag, Heidelberg). The distribution profiles in tissues and the negative response to glucagon treatment further supported the identity of the two enzymes. The present data show that alanine:glyoxilate aminotransferase 2 functions in dimethylarginine metabolism in vivo in rats. << Less

  J. Biol. Chem. 265:20938-20945(1990) [PubMed] [EuropePMC]

  This publication is cited by 15 other entries.

• Co-purification of alanine-glyoxylate aminotransferase with 2-aminobutyrate aminotransferase in rat kidney.

  Okuno E., Minatogawa Y., Kido R.

  Alanine-glyoxylate aminotransferase and 2-aminobutyrate aminotransferase were co-purified from rat kidney to a single protein (about 500-fold purified from the homogenate). The activity ratios of alanine-glyoxylate aminotransferase to 2-aminobutyrate aminotransferase were constant during co-purifi ... >> More

  Alanine-glyoxylate aminotransferase and 2-aminobutyrate aminotransferase were co-purified from rat kidney to a single protein (about 500-fold purified from the homogenate). The activity ratios of alanine-glyoxylate aminotransferase to 2-aminobutyrate aminotransferase were constant during co-purification steps suggesting the 2-aminobutyrate aminotransferase activity was catalysed by only alanine-glyoxylate aminotransferase. The molecular weight of the enzyme was estimated to be approx. 213 000, 220 000 and 236 000 by analytical ultracentrifugation, Sephadex G-150 gel filtration and sucrose density gradient centrifugation, respectively. From the polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate, the enzyme consisted of four apparently similar subunits having a molecular weight of approx. 56 000. The enzyme was almost specific to L-alanine and L-2-aminobutyrate as amino donor and to glyoxylate, pyruvate and 2-oxobutyrate as amino acceptor. The enzyme was identified with rat liver alanine-glyoxylate aminotransferase isoenzyme 2 but not with rat liver alanine-glyoxylate aminotransferase isoenzyme 1 from Ouchterlony double diffusion analysis. Absorption spectra and some kinetic properties of the enzyme were clarified. << Less

  Biochim. Biophys. Acta 715:97-104(1982) [PubMed] [EuropePMC]