Abstract
The R‐type vitamin BIZ‐binding proteins in plasma, serum and granulocytes were characterized by isoelectric focusing. The R proteins from these sources were micro‐heterogenous; they contained isoproteins with the same isoelectric points (PIs) but in different proportions. The increased vitamin B12‐binding capacity of serum as compared with EDTA plasma was due to release of granulocyte R proteins in vitro. Transcobalamin (TC) I and TC III were found to be incompletely separated mixtures of R isoproteins and not separate proteins.

This publication has 20 references indexed in Scilit: