Tightness and Orientation of Vesicles from Guinea‐Pig Kidney Estimated from Reactions of Adenosine Triphosphatase Dependent on Sodium and Potassium Ions

摘要: In order to study the "sidedness" of ligands Na+, K+-ATPase in phosphorylation from [32P]ATP, tight vesicles were prepared guinea pig kidney and partially purified by a two-stage sucrose Ficoll gradient centrifugation procedure. These derived presumably plasma membrane fragments resealed after initial disruption cells during homogenization. Tightness was estimated according activation nonionic detergent, Triton X-100. Treatment with X-100 increased both activity its Na+-dependent [32P]ATP at least three-fold. Activation functions also appeared when shocked osmotically. results suggest that preparation contains major population normal (approximately 75%) which site faces intravesicular solution. response ouabain breakdown phosphoenzyme inhibited treated but not intact ones as if could get binding site. Correspondingly ATP pretreatment presence inorganic phosphate produced less inhibition than those disrupted beforehand. data an everted vesicle fraction 20%). Apparently only small leaky. action K+ on slow. accelerate dephosphorylation effectively ones, had be added before start phosphorylation. This supports view acting side opposite where gamma-phosphoryl group accepted ATP.