The purified plasma membrane ATPase of the yeast Schizosaccharomyces pombe forms a phosphorylated intermediate.

摘要: An acid slab gel electrophoresis method of high-resolving power allows detection a phosphorylated form in the purified ATPase yeast Schizosaccharomyces pombe and identification this catalytic intermediate among different phosphopeptides plasma membrane preparation. At maximum steady state rate MgATP hydrolysis by membrane-bound ATPase, 20 to 40% subunits 100,000 daltons are form, while only 0.8% under same conditions. The reaches level less than 2 s rapidly turns over. substance is cleaved hydroxylamine relatively stable acids but readily hydrolyzed alkaline or alcoholic media. These results suggest that an acylphosphate. phosphorylation reaction has apparent Km value 3.0 mM for 0.6 ATPase. Plasma membranes contain several other minor components whose kinetic behavior typical protein kinase. Artifactual production two forms phenylmethanesulfonyl fluoride-sensitive proteases liberated during cell disruption also demonstrated.