Mechanism of inactivation of gamma-aminobutyric acid aminotransferase by (S,E)-4-amino-5-fluoropent-2-enoic acid.
Evidence for an enamine mechanism of inactivation of pig brain gamma-aminobutyric acid (GABA) aminotransferase by (S,E)-4-amino-5-fluoropent-2-enoic acid is presented. apo-GABA aminotransferase reconstituted with [3H]pyridoxal 5'-phosphate is inactivated by (S,E)-4-amino-5-fluoropent-2-enoic acid and the pH is raised to 12. All of the radioactivity is released from the enzyme as an adduct of the cofactor; no [3H]pyridoxamine 5'-phosphate is generated.
Silverman
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Department of Chemistry, Northwestern University, Evanston, Illinois 60208.
George
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D000612:4-Aminobutyrate Transaminase / Q000037:antagonists & inhibitors*; D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D001921:Brain / Q000201:enzymology*; D055598:Chemical Phenomena; D002621:Chemistry; D002851:Chromatography, High Pressure Liquid; D006863:Hydrogen-Ion Concentration; D011732:Pyridoxal Phosphate / Q000378:metabolism; D013552:Swine
D000596:Amino Acids; D011732:Pyridoxal Phosphate; C050326:4-amino-5-fluoropent-2-enoic acid; D000612:4-Aminobutyrate Transaminase