title: Effect of lead acetate on the kinetics of gamma-glutamyl transpeptidase activity from neonatal rat pup brain.
abstract: The objective of the present investigation was to determine the influence of lead acetate on kinetic parameters of gamma-Glutamyl Transpeptidase (GGT) in brain homogenates from 15 and 30 day old rat pups. Determinations of maximal velocity (Vmax) indicated that the Vmax of GGT from 15 day old pups was 58% of that from 30 day old animals while negligible differences in apparent Km were observed between either group. Addition of lead acetate to GGT preparations from 15 day old pups produced no significant changes in apparent Km for gamma-Glutamyl-p-Nitroanilide (GPNA). However, Vmax was decreased to 35% of control. Addition of lead acetate to GGT incubations from 30 day old pups produced negligible changes in apparent Km for GPNA while Vmax was decreased to 71% of control activity. These data indicate that lead acetate inhibits brain GGT activity from both groups noncompetitively and that brain GGT from 15 day old rats is more susceptible to lead than is that from 30 day old animals.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001921:Brain / Q000201:enzymology*; D005260:Female; D007700:Kinetics; D007854:Lead / Q000633:toxicity*; D051381:Rats; D011919:Rats, Inbred Strains; D005723:gamma-Glutamyltransferase / Q000037:antagonists & inhibitors*
chemical_list: D007854:Lead; D005723:gamma-Glutamyltransferase