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Substrate specificity of cerebral cathepsin D and high‐Mr aspartic endopeptidase
Author(s) -
Azaryan A. V.,
Galoyan A. A.
Publication year - 1988
Publication title -
journal of neuroscience research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.72
H-Index - 160
eISSN - 1097-4547
pISSN - 0360-4012
DOI - 10.1002/jnr.490190213
Subject(s) - pepstatin , endopeptidase , cathepsin o , chemistry , cathepsin d , cathepsin c , cathepsin a , biochemistry , substrate (aquarium) , proteolysis , enzyme , cathepsin e , neprilysin , enkephalinase , stereochemistry , protease , receptor , biology , enkephalin , ecology , opioid
The specificity of action of bovine brain cortex cathepsin D (EC 3.4.23.5) and high‐Mr aspartic endopeptidase (EC 3.4.23.‐) was studied with the vasoactive peptides renin substrate tetradecapeptide (RSTP), substance P (SP), and angiotensins I and II, and with model peptides‐Lys‐Pro‐Ala‐Glu‐Phe‐Phe (NO 2 )‐Ala‐Leu (I), Gly‐Gly‐His‐Phe (NO 2 )‐Phe‐Ala‐Leu‐NH 2 (II), and Abz‐Ala‐Ala‐Phe‐Phe‐pNA (III). Cerebral aspartic peptidases show indentical substrate specificity, cleaving the Leu 10 ‐Leu bond in RSTP and Phe‐Phe in SP and peptide I‐III, and not splitting angiotensins I and II. Because of the higher catalytic efficiency of cathepsin D (K cat value), the specificity constants (K cat /K m ) for cathepsin D‐catalyzed hydrolysis of substrates 1–111 are much higher than those for the high‐Mr enzyme. High‐Mr aspartic peptidase shares a number of properties with cathepsin D (sensitivity to pepstatin, substrate specificity, pH activity profile) and shows partial immunological identity; however, high‐Mr aspartic peptidase has a specific activity 7–10 times lower than that of cathepsin D. The kinetic parameters of proteolysis of model peptides presented indicate that the high‐Mr enzyme may be a complex of a single‐chain cathepsin D with another polypeptide, although the possibility that it is an independent aspartic peptidase cannot be excluded.