Identification of secretin diastereoisomers produced during synthesis

✍ Scribed by Toshiro Tsuda; Mikio Uchiyama; Takashi Sato; Hiroshi Yoshino; Yutaka Tsuchiya; Seiji Ishikawa; Masahiko Ohmae; Sumio Watanabe; Yasuo Miyake

• Publisher: John Wiley and Sons
• Year: 1989
• Tongue: English
• Weight: 403 KB
• Volume: 78
• Category: Article
• ISSN: 0022-3549
• DOI: 10.1002/jps.2600780203

✦ Synopsis

The byproducts P-1 and P-2, which were produced during the synthesis of porcine secretin, were isolated in pure form from the crude secretin by HPLC. These were identified by a combination of amino acid analysis, enzymatic digestion, and isocratic or linear gradient reversed-phase (RP)-HPLC. The amino acid compositions of P1 and P2, determined by amino acid analysis after acid hydrolysis, were found to be the same as those of porcine secretin without distinction between L-and o-amino acids. But, HPLC of their digestive fragments with trypsin and a-chymotrypsin differed from that of secretin. The fragments, S7-,2 of P-1 and SlS2, of P-2 were determined to be different from the corresponding fragments obtained from secretin by HPLC analysis of their digestive fragments. The amino acid composition of each acid hydrolysate, following digestion with o-amino acid oxidase, was found to have less leucine or alanine content than secretin. The HPLC analysis of the fragments from P-1 and P-2 by tryptic and a-chymotryptic digestion showed that they are the same as those from synthetic D-Leul0 secretin or o-Ala17 secretin, respectively. Consequently, P-1 and P-2 are concluded to be the secretin diastereoisomers, o-Leul0 and o-Ala17 secretin, respectively.