A Cyanocobalamin–Protein Complex from Sow's Milk and Desiccated Pig Stomach

Abstract

WE have already reported the partial purification from sow's milk and desiccated pig stomach of proteins which combine with cyanocobalamin and the vitamin B₁₂-like substances having different nucleotide groups¹. Purification of the protein from sow's milk whey was achieved by continuous electro-phoresis on paper². Because of the labile nature of the protein itself, we found it easier to saturate the impure concentrate with cyanocobalamin labelled with cobalt-60 and to isolate the cyanocobalamin–protein complex. Purification of this complex by continuous electrophoresis on paper² was followed by repeated fractionation with isopropyl alcohol at −5°. A recent preliminary note by Wijmenga, Thompson, Stern and O'Connell³, concerning a similar cyanocobalamin–protein from pig gastric mucosa, has prompted us to give a brief account of the properties of our substance isolated from sow's milk. Full experimental details will be published elsewhere.