title: Coenzyme A- and NADH-dependent esterase activity of methylmalonate semialdehyde dehydrogenase.
abstract: Methylmalonate semialdehyde dehydrogenase purified to homogeneity from rat liver possesses, in addition to its coupled aldehyde dehydrogenase and CoA ester synthetic activity, the ability to hydrolyze p-nitrophenyl acetate. The following observations suggest that this activity is an active site phenomenon: (a) p-nitrophenyl acetate hydrolysis was inhibited by malonate semialdehyde, substrate for the dehydrogenase reaction; (b) p-nitrophenyl acetate was a strong competitive inhibitor of the dehydrogenase activity; (c) NAD+ and NADH activated the esterase activity; (d) coenzyme A, acceptor of acyl groups in the dehydrogenase reaction, accelerated the esterase activity; and (e) the product of the esterase reaction proceeding in the presence of coenzyme A was acetyl-CoA. These findings suggest that an S-acyl enzyme (thioester intermediate) is likely common to both the esterase reaction and the aldehyde dehydrogenase/CoA ester synthetic reaction.
authors.affiliation: Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis 46202-5122.
authors.forename: K M
authors.initials: KM
authors.lastname: Popov
authors.forename: N Y
authors.initials: NY
authors.lastname: Kedishvili
authors.forename: R A
authors.initials: RA
authors.lastname: Harris
mesh_terms: D000445:Aldehyde Oxidoreductases / Q000302:isolation & purification / Q000378:metabolism*; D000818:Animals; D003065:Coenzyme A / Q000378:metabolism* / Q000494:pharmacology; D004789:Enzyme Activation; D004950:Esterases / Q000378:metabolism*; D007700:Kinetics; D008099:Liver / Q000201:enzymology*; D050646:Methylmalonate-Semialdehyde Dehydrogenase (Acylating); D009243:NAD / Q000378:metabolism* / Q000494:pharmacology; D010084:Oxidation-Reduction; D051381:Rats
chemical_list: D009243:NAD; D000445:Aldehyde Oxidoreductases; D050646:Methylmalonate-Semialdehyde Dehydrogenase (Acylating); D004950:Esterases; D003065:Coenzyme A