Pseudorenin: A NEW ANGIOTENSIN-FORMING ENZYME

Abstract

A new enzyme, pseudorenin, has been discovered which resembles renin in its ability to form angiotensin I from the synthetic tetradecapeptide renin substrate and from purified hog renin substrate A. Its maximal activity occurs at a much lower pH value than does that of renin. The two enzymes may be easily separated by DEAE-cellulose chromatography. Unlike renin, pseudorenin does not attack substrate A in the presence of serum, nor does it produce angiotensin I from renin substrate as it exists in serum. In contrast to renin, which occurs primarily in the kidney, pseudorenin has been found in every one of the 13 different tissues which have been tested, and also in the plasma. The natural substrate for the new enzyme as well as its physiological function are not known.