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B6db references: 85012493

type Journal Article
authors Watts, S. D.; Atkins, A. M.
title Kinetics of 4-aminobutyrate:2-oxoglutarate aminotransferase from Nippostrongylus brasiliensis
journal Mol Biochem Parasitol
ui 85012493
year (1984)
volume 12
number 2
pages 207-16.
keywords 4-Aminobutyrate Transaminase/isolation & purification/*metabolism
abstract A gamma-aminobutyric acid transferase (4-aminobutyrate:2-oxoglutarate aminotransferase; EC preparation from Nippostrongylus brasiliensis was found to contain only one peak of enzyme activity with a highly basic pI of 10.5 when analysed by isoelectric focusing and chromatofocusing. This material was used in kinetic studies to demonstrate that the parasite enzyme reaction mechanism conforms to the usual binary, non-sequential ('Bi Bi Ping Pong') type found with aminotransferases. The Km for 4-aminobutyrate was 0.33 mM, the Km for 2- oxoglutarate was 0.57 mM and Ki for glutamate was 0.35 mM. In holoenzyme reconstitution experiments with the cofactor, pyridoxal 5- phosphate, the KD was 1.54 microM. The values are comparable to those reported for other tissues. Only 2-oxoglutarate could function as the keto acid substrate whereas several amino acids besides 4-aminobutyrate (beta-alanine, alpha-L-alanine, L-aspartate and L-arginine) could apparently act as substrate although the possible presence of other amino acid:2-oxoglutarate aminotransferases was not excluded. In preliminary studies on the usefulness of conventional substrate analogues as parasite gamma-aminobutyric acid transferase inhibitors only canaline was effective.
last changed 2002/11/04 17:41

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