Vitamin B12 Binding Capacity of Serum in B12 Deficiency.

Abstract

Summary 1. Human serum has been found to have a limited binding capacity for Vit. B₁₂. The B₁₂ binding protein, a seromucoid fraction, appears to be normally only approximately 30-40% saturated. In Vit. B₁₂ deficiency the unsaturated binding capacity is normal but total binding capacity is diminished. 2. It is postulated that; the slower than normal disappearance of Co⁵⁷-B₁₂ from the plasma of B₁₂ deficient individuals is caused by diminished binding capacity in the tissues. The authors wish to express their appreciation to Medical Illustration Service, VA West Side Hospital and to Mr. Lemuel Hall for technical assistance.