Purification and Characterization of Turtle Pepsinogen and Pepsin
| Autor: | Akira Hirasawa, Senarath B. P. Athauda, Kenji Takahashi |
|---|---|
| Rok vydání: | 1996 |
| Předmět: |
Gene isoform
DNA Complementary Molecular Sequence Data Biochemistry Isozyme chemistry.chemical_compound Pepsin Zymogen Animals Humans Amino Acid Sequence Cloning Molecular Molecular Biology Gel electrophoresis Chromatography Binding Sites Pepsinogens Sequence Homology Amino Acid Molecular mass biology General Medicine Pepsin A Turtles Enzyme Activation Isoenzymes Kinetics chemistry Gastric Mucosa Sephadex biology.protein Pepstatin |
| Zdroj: | Journal of Biochemistry. 120:407-414 |
| ISSN: | 0021-924X |
| DOI: | 10.1093/oxfordjournals.jbchem.a021427 |
| Popis: | Pepsinogen was purified from the gastric mucosa of soft-shelled turtle (Trionyx sinensis) by a series of chromatographies on DEAE-cellulose, Sephadex G-100, and Q-Sepharose. Upon chromatography on Q-Sepharose, it was separated into nine isoforms. These isoforms showed a relative molecular mass of approximately 43,000 Da on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and isoforms 4 through 9 contained carbohydrate (approx. 2% each). Insofar as they were examined, their NH2-terminal sequences differed only in showing substitution at a few positions. At pH 2.0, they were rapidly activated to the corresponding isoforms of pepsin in a stepwise manner. The nine isoforms showed similar specific activity toward hemoglobin and hydrolyzed N-acetyl-L-phenylalanyl-L-diiodotyrosine, a good substrate for pepsin A, at somewhat different rates. They were inhibited by pepstatin to various extents, more strongly than human pepsin C but less strongly than human pepsin A. All isoforms appeared to have similar cleavage specificity toward oxidized insulin B chain, which resembled those of both human pepsins A and C. A cDNA clone for one of the zymogen isoforms was isolated and sequenced. The amino acid sequence thus deduced was more homologous with those of mammalian pepsinogens A than those of mammalian pepsinogens C or prochymosin. |
| Databáze: | OpenAIRE |
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