title: Interaction of chloride with yeast aminopeptidase I. Equilibrium binding studies.
abstract: The effect of chloride on metal binding by yeast aminopeptidase I, as well as the binding of chloride to various enzyme forms were studied by means of a micro-centrifugation technique using radioactive 36Cl- as a ligand. Chloride did not significantly alter the binding of activating Zn2+, or binding of Co2+ to the essential metal sites. Both the native Zn2+ enzyme and Co2+-substituted aminopeptidase I bind stoichiometric amounts of C1- (1 Cl-/subunit) with apparent dissociation constants of 0.1-0.2 mM. Additional Cl- was bound at higher concentrations. In contrast to the metal-containing enzyme forms the apoenzyme did not express the high-affinity chloride binding site.
mesh_terms: D000626:Aminopeptidases / Q000378:metabolism*; D001665:Binding Sites; D002712:Chlorides / Q000378:metabolism* / Q000494:pharmacology; D003035:Cobalt / Q000378:metabolism; D007700:Kinetics; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins; D015032:Zinc / Q000378:metabolism
chemical_list: D002712:Chlorides; D029701:Saccharomyces cerevisiae Proteins; D003035:Cobalt; D000626:Aminopeptidases; C019689:APE1 protein, S cerevisiae; D015032:Zinc