Distribution of platelet glycoproteins and phosphoproteins in hydrophobic and hydrophilic phases in Triton X-114 phase partition

Abstract

Platelets, either unlabelled, surface-labelled by the periodate NaB3H4 method or metabolically labelled with 32P were solubilized in Triton X-114 and partitioned into aqueous and detergent phases. The phases were analysed by two-dimensional polyacrylamide gel electrophoresis followed by silver-staining, fluorography or indirect autoradiography. Each of the phases contains a distinct set of proteins. The surface-labelled glycoproteins partition into the hydrophobic phase with the notable exceptions of glycoproteins Ib and GP17(5.8-6.5) and minor amounts of a few others. The phosphoproteins which undergo increased phosphorylation on platelet activation in general separate in the hydrophobic phase, while higher molecular weight phosphoproteins were principally in the hydrophilic phase. This method might be used as a first step in purifying many platelet components.