69(P47) 韓国産カキから分離した苦みペプチドの構造と合成(ポスター発表の部)

概要

論文の詳細を見る
A new cyclic peptide having a strong bitter taste was isolated from oysters, Crassostrea gigas cultured in Gamak Bay on the southern coast of Korea. The peptide was isolated from both frozen and canned oysters as a colorless amorphous solid after several steps of chromatography. A molecular formula C_<43>H_<61>N_7O_8S was deduced from high resolution FAB MS and NMR data. Presence of six amino acids and a unique hydantoin structure in the molecule was elucidated by NMR spectrometry. Configurations of α-methines in two leucine, one N-methylphenylalanine and one methionine sulfoxide moieties obtained by acid hydrolysis of the peptide were determined to be L by derivatizing the amino acids with Marfey's reagent and analyzing on an HPLC column. Diastereomeric dipeptides (7a, 7b, 7c and 7d) composed of lysine and phenylalanine in a hydantoin structure were synthesized. Chiral HPLC analysis as well as NMR and CD data of these dipeptides indicated that the absolute configuration of lysine was D, while that of phenylalanine was L. To confirm the structure of 1, total synthesis was accomplished according to Scheme 2. The ^1H NMR spectrum of the synthetic peptide was identical with that of the bitter peptide isolated from the oysters except for the asymmetric ratio at sulfoxide in methionine sulfoxide. Thus, the structure of 1 was unambiguously elucidated as shown in Fig. 1.
天然有機化合物討論会の論文
1999-09-01