Studies of self-inactivation of bovine seminal fluid NAD glycohydrolase.
Bovine seminal fluid NAD glycohydrolase (NADase) was observed to be rapidly inactivated during catalytic hydrolysis of the substrate NAD. The first-order rate constant for the self-inactivation process was independent of enzyme concentration. The enzyme self-inactivation was a turnover-related process and the number of moles of NAD hydrolyzed required for inactivation was proportional to the enzyme concentration. A number of dinucleotides serving as substrates for the enzyme also promoted self-inactivation. The self-inactivation was an irreversible process having a different rate-limiting step from NAD hydrolysis and was not related to the reversible binding of products and substrate-competitive inhibitors. Modification of arginine residues of the enzyme resulted in the loss of NAD hydrolase activity with no differential effect on the self-inactivation process.
Anderson
B M
BM
Yost
D A
DA
D000818:Animals; D002417:Cattle; D003931:Diacetyl / Q000494:pharmacology; D006868:Hydrolysis; D007700:Kinetics; D008297:Male; D009244:NAD+ Nucleosidase / Q000378:metabolism*; D012661:Semen / Q000201:enzymology*; D013696:Temperature; D013997:Time Factors
D009244:NAD+ Nucleosidase; D003931:Diacetyl