title: Effect of amino acids on inhibition of lactate dehydrogenase-X by gossypol.
abstract: Gossypol acetic acid (GAA) has been shown to have male antifertility effects, but there are pronounced differences among animal species. In the search of endogenous effector molecules, which interfere with the functions of GAA, we have studied the in vitro effect of various amino acids on the inhibition of the purified LDH-X by GAA. Histidine, cysteine and glycine were shown to block the effect of GAA. The effects of these amino acids were concentration dependent. Histidine and glycine protection was found to be complex type in which both the Km and Vmax were decreased compared to control. Arginine, glutamic acid, phenylalanine and valine were found to be ineffective against the inhibitory action of GAA.
authors.affiliation: Department of Biochemistry, The Aga Khan University, Karachi, Pakistan. scm@sihl.sdnpk.undp.org
authors.forename: M H
authors.initials: MH
authors.lastname: Javed
authors.forename: M A
authors.initials: MA
authors.lastname: Khan
mesh_terms: D000596:Amino Acids / Q000494:pharmacology*; D000818:Animals; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006041:Goats; D006072:Gossypol / Q000031:analogs & derivatives* / Q000494:pharmacology; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000037:antagonists & inhibitors*; D008297:Male; D013089:Spermatocidal Agents / Q000494:pharmacology*; D013737:Testis / Q000201:enzymology
chemical_list: D000596:Amino Acids; D004791:Enzyme Inhibitors; D007527:Isoenzymes; D013089:Spermatocidal Agents; D007770:L-Lactate Dehydrogenase; D006072:Gossypol; C028178:gossypol acetic acid