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PROPERTIES OF AMINOPEPTIDASE FROM JAPANESE CLASSIFIED BARLEY FLOUR
Author(s) -
KAWAGUCHI MAKIKO,
DOI HIROSHI
Publication year - 2003
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.2003.tb00273.x
Subject(s) - pepstatin , aminopeptidase , leupeptin , leucine , hydrolysis , chemistry , enzyme , substrate (aquarium) , protease , arginine , biochemistry , chromatography , peptide , lysine , hydrolysate , food science , amino acid , biology , ecology
An aminopeptidase (AP) was purified from classified barley flour obtained from the outer layer of Japanese grain. To characterize the enzyme, the substrate specificity and pH optimum were determined with 9 aminoacyl‐p‐nitroanilide (p‐NA) and 6 aminoacyl‐β‐naphthylamide (β‐NA). Furthermore, the effects of inhibitors and the hydrolysis of natural substrates were investigated. The optimum pH was between 6.5 and 8.0 in all cases in which these artificial substrates were used. Phe‐β‐NA had the highest affinity for the enzyme and the Km value was 0.084 mM. The enzyme also showed a strong preference against leucine‐, arginine‐, and lysine‐p‐NA (Km = 0.18 mM, 0.10 mM, and 0.48 mM, respectively). Chymostatin slightly inhibited the activity, whereas AP was not affected by leupeptin and pepstatin A. The enzyme did not hydrolyze the proteins tested, but it cleaved peptide hormones.