Discovery of a γ‐carboxyglutamic acid‐containing protein in human spermatozoa

Abstract
Here we describe the identification of a γ-carboxyglutamic acid-containing protein in human spermatozoa. After thermal decarboxylation the protein is a good substrate for vitamin K-dependent carboxylase from various origins. A quick purification procedure for the decarboxylated protein is presented and in a preliminary characterization we have established its M r, (28000–30000) and its amino acid composition.