Intrinsic Factor Studies I. Paper Electrophoresis of Mixture of Gastric Juice and Radioactive Vitamin B12.∗

1. Results of paper electrophoresis of mixtures of radioactive vit. B12and concentrated human gastric juice demonstrate that the radioactive B12 is bound to a component of gastric juice which is not one of the major protein peaks and moves toward the anode. This behavior of the vit. B12was not noted when it was mixed with saline or serum. 2. This localization of vit. B12to a specific portion of gastric juice by paper electrophoresis may be a clue to the further identification of the intrinsic factor of Castle.