Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P17174 (aspartate aminotransferase)
 14,872 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Isocitrate lyase (EC 4.1.3.1) and malate synthase (EC 4.1.3.2), the two enzymes characteristic of the glyoxylate cycle, were demonstrated in promastigotes of five species of Leishmania (L. brasiliensis, L. donovani, L. mexicana, L. tarentolae, and L. tropica). Both enzymes were present in cells grown in a medium containing 10 mM glucose. Substitution of glucose with 20 mM acetate did not enhance enzyme levels. Acetate was readily taken up and metabolized by the cells. The distribution of label from acetate into various intermediary metabolites indicates a functional glyoxylate cycle and its role in gluconeogenesis/glyconeogenesis. The glyoxylate cycle in conjunction with alanine-glyoxylate aminotransferase and glyoxylate-aspartate aminotransferase could also be important in providing glyoxylate, the precursor for glycine biosynthesis.
 ...
PMID:Evidence for a functional glyoxylate cycle in the leishmaniae. 69 79

The activity of enzymes of glycine and alanine synthesis (glutamate-pyruvate aminotransferase, aspartate-beta-decarboxylase, threonine aldolase, serine hydroxymethyltransferase, alanine-glyoxylate aminotransferase, aspartate aminotransferase) is studied in haemolymph, fat body, fibroin and sericine divisions of silk gland of silkworm Bombyx mori at terminal period of larva development. Alanine-glyoxylate aminotransferase activity in fibroin division of silk gland (34,6 mu mole of glycine/mg of protein/min-10(-3)), alanine aminotransferase--in sericine division (36,0 mu mole of alanine/mg of protein/min-10(-3)) aspartate aminotransferase 27,3 mu mole of glutamic acid/mg of protein/min-10(-3)) and alanine aminotransferase (35,8 mu mole of alanine/mg of protein/min-10(-3)) on fat body. The ratio of alanine-glyoxylate aminotransferase/glutamate-pyruvate aminotransferase activities in posterior division of silk gland is near to glycine/alanine ratio in silk fibroin. The character of the enzymes activity in silkworm tissues correlates with the silk formation rate.
 ...
PMID:[Glycine and alanine synthesis enzymes in the tissues of the silkworm during its development]. 99 78

The gene encoding serine-glyoxylate aminotransferase, one of key enzymes for the assimilation of one-carbon compounds in methylotrophs, and its flanking regions were isolated from an obligate methylotrophic bacterium, Hyphomicrobium methylovorum GM2. Nucleotide sequencing of the recombinant plasmids revealed that the serine-glyoxylate aminotransferase gene encodes a 405-amino-acid protein with a calculated molecular mass of 43880 Da. The amino acid sequence of the enzyme showed identity to the sequences of serine-glyoxylate aminotransferase of Methylobacterium extorquens AM1 (57%), aspartate aminotransferase of Methanobacterium thermoformicicum (31%), human peroxisomal alanine-glyoxylate aminotransferase (27%), and serine-pyruvate aminotransferase of rat liver mitochondria (33%). The recombinant plasmid, which was constructed by ligation of the cloned gene and an expression vector pKK223-3, was introduced into Escherichia coli HB101. The recombinant enzyme was purified from transformed E. coli cells and analyzed by immunological and enzymological methods. The overexpressed enzyme was indistinguishable from the wild-type enzyme isolated from H. methylovorum GM2.
 ...
PMID:Cloning and expression of the gene for serine-glyoxylate aminotransferase from an obligate methylotroph Hyphomicrobium methylovorum GM2. 889 80

Several halogenated alkenes are metabolized in part to cysteine S-conjugates, which are mitochondrial toxicants of kidney and, to a lesser extent, other organs. Toxicity is due to cysteine S-conjugate beta-lyases, which convert the cysteine S-conjugate into pyruvate, ammonia and a reactive sulphur-containing fragment. A section of the human population is exposed to halogenated alkenes. To understand the health effects of such exposure, it is important to identify cysteine S-conjugate beta-lyases that contribute to mitochondrial damage. Mitochondrial aspartate aminotransferase [Cooper, Bruschi, Iriarte and Martinez-Carrion (2002) Biochem. J. 368, 253-261] and mitochondrial branched-chain aminotransferase [Cooper, Bruschi, Conway and Hutson (2003) Biochem. Pharmacol. 65, 181-192] exhibit beta-lyase activity toward S -(1,2-dichlorovinyl)-L-cysteine (the cysteine S-conjugate of trichloroethylene) and S -(1,1,2,2-tetrafluoroethyl)-L-cysteine (the cysteine S-conjugate of tetrafluoroethylene). Turnover leads to eventual inactivation of these enzymes. Here we report that mitochondrial L-alanine-glyoxylate aminotransferase II, which, in the rat, is most active in kidney, catalyses cysteine S-conjugate beta-lyase reactions with S -(1,1,2,2-tetrafluoroethyl)-L-cysteine, S -(1,2-dichlorovinyl)-L-cysteine and S -(benzothiazolyl-L-cysteine); turnover leads to inactivation. Previous workers showed that the reactive-sulphur-containing fragment released from S -(1,1,2,2-tetrafluoroethyl)-L-cysteine and S -(1,2-dichlorovinyl)-L-cysteine is toxic by acting as a thioacylating agent - particularly of lysine residues in nearby proteins. Toxicity, however, may also involve 'self-inactivation' of key enzymes. The present findings suggest that alanine-glyoxylate aminotransferase II may be an important factor in the well-established targeting of rat kidney mitochondria by toxic halogenated cysteine S-conjugates. Previous reports suggest that alanine-glyoxylate aminotransferase II is absent in some humans, but present in others. Alanine-glyoxylate aminotransferase II may contribute to the bioactivation (toxification) of halogenated cysteine S-conjugates in a subset of individuals exposed to halogenated alkenes.
 ...
PMID:L-alanine-glyoxylate aminotransferase II of rat kidney and liver mitochondria possesses cysteine S-conjugate beta-lyase activity: a contributing factor to the nephrotoxicity/hepatotoxicity of halogenated alkenes? 1285 50

Pyridoxamine-pyruvate aminotransferase is a PLP (pyridoxal 5'-phosphate) (a coenzyme form of vitamin B6)-independent aminotransferase which catalyses a reversible transamination reaction between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The gene encoding the enzyme has been identified, cloned and overexpressed for the first time. The mlr6806 gene on the chromosome of a symbiotic nitrogen-fixing bacterium, Mesorhizobium loti, encoded the enzyme, which consists of 393 amino acid residues. The primary sequence was identical with those of archaeal aspartate aminotransferase and rat serine-pyruvate aminotransferase, which are PLP-dependent aminotransferases. The results of fold-type analysis and the consensus amino acid residues found around the active-site lysine residue identified in the present study showed that the enzyme could be classified into class V aminotransferases of fold type I or the AT IV subfamily of the alpha family of the PLP-dependent enzymes. Analyses of the absorption and CD spectra of the wild-type and point-mutated enzymes showed that Lys197 was essential for the enzyme activity, and was the active-site lysine residue that corresponded to that found in the PLP-dependent aminotransferases, as had been suggested previously [Hodsdon, Kolb, Snell and Cole (1978) Biochem. J. 169, 429-432]. The K(d) value for pyridoxal determined by means of CD was 100-fold lower than the K(m) value for it, suggesting that Schiff base formation between pyridoxal and the active-site lysine residue is partially rate determining in the catalysis of pyridoxal. The active-site structure and evolutionary aspects of the enzyme are discussed.
 ...
PMID:Molecular cloning, expression and characterization of pyridoxamine-pyruvate aminotransferase. 1654 75