Complex of intrinsic factor and B12 in human ileum during vitamin B12 absorption

Publisher Website
Google Scholar
Abstract
During absorption studies in man, the size and biological characteristics of at least some of the 57Co-labeled vitamin B12 found in extracts of ileum were identical with those of a complex of human intrinsic factor (IF) and vitamin B12. Although the 57Co12 in the ileum combined with the antibody IF, its behavior during combination differed from that of normal human gastric juice with vitamin B12. The IF-B12 complex (mol. wt. approximately 60,000) becomes intimately associated with the wall of the ileum during absorption of vitamin B12 in vivo and may enter the wall itself. During this process its biological properties are unchanged, but its immunological characteristics appear to be modified.