Five pepsinogens were purified from gastric mucosa of Japanese monkey by DEAE-cellulose column chromatography and Sephadex G-100 gel filtration. Each was shown to be homogeneous by polyacrylamide disc gel electrophoresis. They were designated as pepsinogens I, II, III-l, III-2, and III-3, respectively, based on the elution profile -on DEAE-cellulose chromatography. The molecular weights of pepsinogens I and II were 48, 000 and 43, 000, respectively, and those of the other three were 40, 000. Each pepsinogen was converted to pepsin [EC 3.4.23.1] by acidification, and some characteristics, e.g. the pH dependence of activity, sensitivity to various inhibitors, stability to alkali, and hydrolytic activity toward N-acetyI-L-phenylalanyl-3, 5-diiodo-L-tyrosine (APDT), were determined. The characteristics of pepsins I and II were the same, and those of pepsins III-l, III-2, and III-3 were similar.. Pepsin III-3 showed high stability to alkali (pH 8.0), while the others were less stable. Each pepsin hydrolyzed APDT and was inhibited by acid protease-specific inhibitors, e.g. pepstain, diazoacetyl-DL-norleucine methyl ester (DAN), 1, 2-epoxy-3-(p-nitrophenoxy)propane (EPNP), and P-bromophenacyl bromide. The amino acid compositions of these pepsinogens and pepsins were analyzed. The compositions of pepsins I and II were the same, indicating that they are the same protein, and those of pepsins III-l, III-2, and III-3 resembled that of human pepsin. The diversity of pepsinogens and pepsins is discussed in comparison with pepsinogens and pepsins from other animals.
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Kageyama et al. (1976) studied this question.