Comparison of antigenic and chemical similarities between vitamin B 12-binders of human gastric juice and vitamin B 12-binders extracted from the mucosa of chimpanzee ( Pan troglodytes) stomach

Abstract

Normal human gastric juice and an extract of chimpanzee fundus were studied by chromatography on Sephadex G-100 columns. Two B 12-binders were demonstrated in both human gastric juice and chimpanzee fundus extract, one which eluted with proteins in the mol. wt. range of 90 000, the second which eluted with proteins having a mol. wt. of approx. 50 000. The small B 12-binder in both human gastric juice and chimpanzee fundus extract reacted with the two antibodies found in serum of pernicious anemia patients that neutralize human intrinsic factor. When chimpanzee fundus extract was used as a source of intrinsic factor to determine the titer of the antibody in pernicious anemia serum which neutralizes the B 12 combining site of intrinsic factor, identical titers were obtained as when human gastric juice was used as the source of intrinsic factor.