Abstract
Conclusions
An assay of the intrinsic factor activity of native, acid gastric juices of humans by means of the scintillation measurements of the hepatic uptake of radioactive vit. B12 on patients with pernicious anemia in remission, has confirmed the thermolability of the human intrinsic factor and its destruction or inactivation by boiling at pH 1.2-1.4 for 30 minutes. Similar studies done on intrinsic factor concentrates from hog stomach revealed inactivation or destruction of its intrinsic factor activity by boiling in 1/10 normal HCl (pH about 1.2) for 30 minutes, but a relative heat stability of the same preparations, when boiled in water at a neutral pH of about 6.0. Therefore, the thermostability of some of the “intrinsic factor concentrates with vit. B12” from hog stomach, when boiled in water, is apparently not due to the prior combination with vit. B12 because it can also be demonstrated on concentrates boiled in water prior to addition of the vitamin.
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