Purification and Properties of Hog-Kidney 3,4-Dihydroxyphenylalanine Decarboxylase

Abstract

A procedure for the purification of 3,4-dihydroxyphenylaianine decarboxylase from hog kidney is described. Enzyme fractions with 190-fold greater specific activity than in the supernatant portion of kidney cortex have been obtained. Such fractions yield a single protein peak by disc gel electrophoresis and by continuous electrophoresis in acrylamide gel. The purified enzyme is partially resolved with respect to its coenzyme pyridoxal phosphate. It appears to consist of two polypeptide chains of unequal size. The purified enzyme catalyzes the decarboxylation of dihydroxyphenylalanine, 5-hydroxytryptophan, erythro-dihydroxyphenylserine, m-tyrosine, and o-tyrosine, but not of p-tyrosine and threo-dihydroxyphenylserine.