Chymotryptic digest of papain. III. Amino acid sequence of six peptides.
نویسندگان
چکیده
Dinitrophenylation-The amino-terminal residue was determined on. a sample of the peptide before desalting. Approximately 1 pmole of the peptide was submitted to dinitrophenylation for 6 hours with the reaction mixture maintained at pH 8.5 with the aid of a pH stat. The solution was evaporated to dryness and triturated with dry ethyl acetate. Estraction was continued until all the yellow color was removed. After evaporation of the extract only traces of salt were found. After hydrolysis with 6 N HCl for 20 hours at 105” and removal of dinitrophenol by sublimation, DNPl-glycine was obtained in 20% yield. Edman Degradation-Two pmoles of desalted peptide were submitted to three stages of degradation. The reaction with phenylisothiocyanate was followed on the pH stat and was continued for several hours until the alkali uptake was identical to that of the blank. Cyclisation with 2 N HCl lasted 22 hours for the first stage, 6 hours and 24 hours for the second and third stages, respectively. PTH-glycine was identified after paper chromatography in solvent System F and represented the amino-terminal residue of the peptide. The second residue was identified as valine after paper chromatography in solvent Systems A and F. The identification of the first two residues was confirmed by amino acid analysis of the peptide residue. After two stages of degradation, the composition in molar ratios was
منابع مشابه
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ورودعنوان ژورنال:
- The Journal of biological chemistry
دوره 235 شماره
صفحات -
تاریخ انتشار 1960