title: Control of ram sperm adenylate cyclase by divalent cations.
abstract: The adenylate cyclase activity of ram sperm increased on freeze-thawing and the enzyme was stable at 0 degrees C. Its activity was stimulated by Mn2+, Zn2+, Co2+, Mg2+ and Ca2+ in descending order of activity. The enzyme was insensitive to fluoride when Mn2+ concentration was in excess. Mn2+-stimulated enzyme activity was decreased by the simultaneous addition of Co2+, or Cd2+, or Ni2+, and particularly Cu2+. Sulfhydryl compounds (viz. dithiothreitol, glutathione, dithiocarbamate, 2-mercaptoethanol, ergothioneine and cysteine) and chelating agents (viz. D-penicillamine and 8-hydroxyquinoline) were effective, to varying degrees, in overcoming the inhibition by Cu2+. Ca2+ augmented the stimulatory effect of Mg2+, Co2+, Zn2+ and Mn2+ on enzyme activity.
authors.affiliation: Department of Veterinary Physiology, University of Sydney, N.S.W.
authors.forename: P P
authors.initials: PP
authors.lastname: Goh
authors.forename: I G
authors.initials: IG
authors.lastname: White
mesh_terms: D000262:Adenylyl Cyclases / Q000378:metabolism*; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002413:Cations, Divalent / Q000378:metabolism; D002614:Chelating Agents / Q000494:pharmacology; D008297:Male; D012756:Sheep / Q000502:physiology*; D013094:Spermatozoa / Q000201:enzymology*; D013438:Sulfhydryl Compounds / Q000494:pharmacology
chemical_list: D002413:Cations, Divalent; D002614:Chelating Agents; D013438:Sulfhydryl Compounds; D000262:Adenylyl Cyclases; D002118:Calcium