Binding to specific receptors on oocyte plasma membranes by serum phosvitin‐lipovitellin

Abstract

Specific binding sites for the serum complex of phosvitin and lipovitellin have been shown to exist on the outer surface of rapidly growing chicken oocytes. The existence and specificity of these sites were demonstrated by competition for binding to unfixed oocyte membrane fragments and by displacement of already bound and labeled phosvitin‐lipovitellin from formaldehyde‐fixed membranes. Only unlabeled phosvitin‐lipovitellin competed with the ¹²⁵I‐labeled complex for binding to the fragments or displacement of bound label; IgG isolated from egg yolks and bovine serum albumin were ineffective.