Reaction of the anionic acetylation agent methyl acetyl phosphate with D-3-hydroxybutyrate dehydrogenase.
Biochem Cell Biol
; 64(5): 434-40, 1986 May.
Article
en En
| MEDLINE
| ID: mdl-3718711
ABSTRACT
Methyl acetyl phosphate is a competitive inhibitor of the reduction of acetoacetate by D-3-hydroxybutyrate dehydrogenase. The material also irreversibly inactivates the enzyme. The kinetics of the inactivation are consistent with methyl acetyl phosphate acetylating the conjugate base of a hydrogen bond donor. Protection offered by a substrate analogue (methyl acetonylphosphonate) in the presence of coenzyme implicates reaction at the cationic active site. Reversible protection by the amino group reagent 2,3-dimethylmaleic anhydride suggests that methyl acetyl phosphate reacts with an amino group. Sulfhydryl reagents and acetyl phosphate, a poorer acetylating agent, do not inactivate the enzyme. The pH dependence of the inactivation suggests that the acetylation occurs at a site that has a pKa of 8.2. The utility of methyl acetyl phosphate and other acyl phosphate monoesters in reacting with lysines adjacent to cationic sites of enzymes, hemoglobin, and histones is noted.
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Base de datos:
MEDLINE
Asunto principal:
Compuestos Organofosforados
/
Ácido Fosfonoacético
/
Hidroxibutirato Deshidrogenasa
Idioma:
En
Revista:
Biochem Cell Biol
Asunto de la revista:
BIOQUIMICA
Año:
1986
Tipo del documento:
Article