Characteristics of Two Different Vitamin D-Dependent Calcium Binding Proteins in Rat Intestinal Mucosa

Abstract

Characteristics of two different vitamin D-dependent calcium binding proteins in rat intestinal mucosa were studied using polyacrylamide disc gel electrophoresis and Scatchard method. The smaller vitamin D-dependent protein, found predominantly in the duodenum and jejunum, showed electrophoretic mobility similar to that found in other mammalian species, and has one high affinity site with an apparent intrinsic affinity constant of 2.5×10^5M^<-1>. On the other hand, the larger vitamin D-dependent protein, found mainly in jejunum and ileum, showed electophoretic mobility similar to that found in chick, and has about 3.6 high affinity sites with an apparent intrinsic affinity constant of 1.2×10^6M^<-1> and 85 sites with an affinity about 2.2×10^4M^<-1>.