Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Examination of 10 enzymes from 8 stocks of Trypanosoma brucei showed that procyclic forms could be substituted for bloodstream forms in isoenzyme studies. T. b. gambiense procyclic forms cultured in vitro offer a better source of material for genetic investigations because this species is usually of low infectivity and virulence to laboratory rodents. Using 6 stocks of T. b. gambiense and 2 stocks of T. b. brucei, enzyme patterns of bloodstream and procyclic forms were identical for isocitrate dehydrogenase, malic enzyme, two nucleoside hydrolases (utilizing inosine and deoxyinosine respectively), phosphoglucomutase and superoxide dismutase. Procyclic forms appeared to have greater threonine dehydrogenase activity than bloodstream forms. Consistent differences between bloodstream and culture forms were observed for alanine aminotransferase, aspartate aminotransferase and malate dehydrogenase. These agreed with known differences in the metabolism of procyclic and bloodstream forms.
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PMID:The substitution of procyclic for bloodstream form Trypanosoma brucei gambiense in isoenzyme studies. 238 16

Multilocus enzyme electrophoresis was developed to evaluate the genetic diversity of 71 human strains and 17 animal strains of Clostridium perfringens. Crude protein extracts, obtained by sonication of washed bacteria, were analyzed by polyacrylamide-agarose gel electrophoresis to characterize electrophoretic mobility variants of seven enzymes (esterase, glutamate dehydrogenase, glutamic-oxaloacetic transaminase, nucleoside phosphorylase, phosphoglucose isomerase, phosphoglucomutase, threonine dehydrogenase). Genetic diversity of the enzyme loci ranged from 0.340 to 0.813. Sixty-nine electrophoretic types were described among the 88 strains tested and the index of discrimination was 0.994. All strains were typable, and epidemiological relationships between isolates could be established. This method showed a fair correlation with esterase electrophoretic typing based on hydrolytic and electrophoretic polymorphism of esterases. This work demonstrates that multilocus enzyme polymorphism is a reliable and discriminant marker of genetic diversity of strains of C. perfringens.
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PMID:Multilocus enzyme typing of human and animal strains of Clostridium perfringens. 808 23

2-Amino-3-ketobutyrate CoA ligase (KBL, EC 2.3.1.29) is a pyridoxal phosphate (PLP) dependent enzyme, which catalyzes the second reaction step on the main metabolic degradation pathway for threonine. It acts in concert with threonine dehydrogenase and converts 2-amino-3-ketobutyrate, the product of threonine dehydrogenation by the latter enzyme, with the participation of cofactor CoA, to glycine and acetyl-CoA. The enzyme has been well conserved during evolution, with 54% amino acid sequence identity between the Escherichia coli and human enzymes. We present the three-dimensional structure of E. coli KBL determined at 2.0 A resolution. KBL belongs to the alpha family of PLP-dependent enzymes, for which the prototypic member is aspartate aminotransferase. Its closest structural homologue is E. coli 8-amino-7-oxononanoate synthase. Like many other members of the alpha family, the functional form of KBL is a dimer, and one such dimer is found in the asymmetric unit in the crystal. There are two active sites per dimer, located at the dimer interface. Both monomers contribute side chains to each active/substrate binding site. Electron density maps indicated the presence in the crystal of the Schiff base intermediate of 2-amino-3-ketobutyrate and PLP, an external aldimine, which remained bound to KBL throughout the protein purification procedure. The observed interactions between the aldimine and the side chains in the substrate binding site explain the specificity for the substrate and provide the basis for a detailed proposal of the reaction mechanism of KBL. A putative binding site of the CoA cofactor was assigned, and implications for the cooperation with threonine dehydrogenase were considered.
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PMID:Three-dimensional structure of 2-amino-3-ketobutyrate CoA ligase from Escherichia coli complexed with a PLP-substrate intermediate: inferred reaction mechanism. 1131 37