PEPSINOGENS A, C, AND D FROM SMOOTH DOGFISH

Four pepsinogens have been separated from the stomach mucosae of the smooth dogfish by chromatography on DEAE-cellulose. Pepsinogen B, which at pH 2 had enzymic activity toward the synthetic substrate, carbobenzoxyglutamyltyrosine, first emerged followed by pepsinogens D, A, and C with potential enzymic activity toward protein substrates. The latter three precursors were purified further by DEAE-cellulose and Sephadex chromatography. Their molecular weights, determined by ultracentrifugal analysis, were found to be approximately 42,000. Their amino acid composition showed a predominance of acidic over basic residues. In these respects, the dogfish pepsinogens resemble the swine and bovine zymogens. The compositions of pepsinogens A and D were similar to each other and differed from pepsinogen C. The immunological experiments with antipepsinogens A, D, and C also indicated that pepsinogens A and D were similar and that pepsinogen C was distinct. © 1969, American Chemical Society. All rights reserved.