Original Article : Gamakamide C and D as Two New Analogues of Bitter-Tasting Cyclic Peptide with Hydantoin Structure from Oyster Crassostrea gigas = Original Article : Gamakamide C and D as Two New Analogues of Bitter-Tasting Cyclic Peptide with Hydantoin Structure from Oyster Crassostrea gigas

다국어 초록 (Multilingual Abstract)

Two new bitter-tasting cyclic peptides comprising six amino acids, namely gamakamide C and D, were isolated from cultured oysters Crassostrea gigas. Dimethylaminoazobenzene sulfonyl-amino acid analysis detected Val and Leu in gamakamide C and Ile and Leu in gamakamide D. The molecular formula of gamakamide C was determined as C43H60N7O8S by high-resolution fast atom bombardment mass spectroscopy (HR FAB-MS) ([M + H]+ m/z 822.4200 Δ -2.4 mmu), and that of gamakamide D was determined as C43H62N7O8S by HR FAB-MS ([M + H]+ m/z 836.4379 Δ -2.0 mmu). Comparison of amino acid analyses and fragment ions by MS/MS among gamakamide C, D, and E (known), the structures of gamakamide C and D were confirmed as -l-Val-l-Met(SO)-l-NMe-Phe-l-Leu-d-Lys-l-Phe- and -l-Ile-l-Met(SO)-l-NMe-Phe-l-Leu-d-Lys-l-Phe-, respectively.