Abstract
The nature of proteinase of the infant stomach was examined by paper electrophoresis (EP). In EP at pH2.5, near the isoelectric point of pepsin, the extract of infant stomach exhibited an enzyme fraction with strong activity of hydrolysis near the base line on the paper. In mixed EP with Hansen's rennent, three frctions developed. Of them, one fraction was derived from the stomach extract and the others were from rennin. On a piece of paper of EP at pH4.6, pepsin from the horse and that from the sheep were not seperated from pepsin of swine, but that of human infant sometimes formed a separate fraction.
In the infant stomach, pepsin was a main proteinase and no rennin was secreted, because by paper EP at ph corresponding to the isoelectric point of pepsin, proteinase of the infant stomach did not move and had strong activity of hydrolysis and weak activity of coagulation. No fraction of cathepsin appeared on any paper of EP.
