Abstract
Cattle and horse plasma samples of known post-albumin types were radiolabeled with 14C-vitamin D3. These samples were analyzed by polyacrylamide gel electrophoresis followed by autoradiography. The patterns observed were identical to those of post-albumin variants. The polymorphic post-albumin protein of cattle and horse was identified as the vitamin D binding protein and homologous to the Gc protein of human plasma.