Abstract
P3 and P4 substances were collected from fresh urine of normal male subjects by the techniques of saturation with acetone and precipitation with lead acetate. In addition, FII was fractionated out chromatographically from P3, and was found to have a strong activity in producing cardiac arrest in the frog. It was possible to obtain evidence that the activity of FII is the essence of that of P3 and that FII consists of a single or nearly single substances as chromatographically shown. FII fraction appears to be a peptide of low molecular weight with lysine and tyrosine among the constituents. P4 had no such activity as FII or P3 but suggested the glucoside-type bond. Treatment with acids and heat showed that P4 originates from the same substances as glucuronic acid. Partial hydrolysis of FII resulted in two different ninhydrin-positive components in addition to lysine and tyrosine. Two ninhydrin-positive substances were found among the partial hydrolytes of P4. It is suggested that there is a resemblance in basic structure between FII and P4.
