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DISTRIBUTION AND PROPERTIES OF ANGIOTENSIN CONVERTING ENZYME OF RAT BRAIN
Author(s) -
Yang H.Y. T.,
Neff N. H.
Publication year - 1972
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1972.tb01298.x
Subject(s) - enzyme , enzyme assay , angiotensin converting enzyme , biochemistry , chemistry , renin–angiotensin system , substrate (aquarium) , microsome , medicine , endocrinology , biology , ecology , blood pressure
— Angiotensin converting enzyme of rat brain was studied using Hip‐His‐Leu as substrate. The highest specific activity of the enzyme was associated with the microsomal fraction. The specific activity of the microsomal enzyme in several regions of the rat brain varied significantly. For example, the specific activities of the striatal and pituitary enzymes were about 10‐fold greater than that of the cerebral cortical enzyme. The enzyme required chloride ion; moreover, activity was inhibited in the presence of disodium EDTA or O‐phenanthroline, effects suggesting that the converting enzyme of brain is a metalloprotein. SQ‐20881, a nonapeptide that inhibits converting enzyme in peripheral tissue, was a potent inhibitor of the enzyme of brain. In addition to Hip‐His‐Leu, the microsomal fraction was capable of liberating C terminal dipeptides from angiotensin I, Hip‐Gly‐Gly and Z‐Gly‐ Gly‐Val. The broad substrate specificity of the enzyme suggests that, in addition to the possible contribution of the enzyme to the brain renin‐angiotensin system, other naturally occurring peptides might also be substrates for the enzyme.