Onozato Mayu, Takaura Tomoya, Shinohara Wataru, Tsukada Takehiro, Sakamoto Tatsuya, Okoshi Kenji, Fukushima Takeshi
Department of Analytical Chemistry, Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi-shi, 274-8510, Chiba, Japan.
Chiba Municipal Chiba High School, 9-46-1 Konakadai, Inage-ku, Chiba-shi, 263-0043, Chiba, Japan.
Sci Rep. 2025 Jul 14;15(1):25415. doi: 10.1038/s41598-025-10379-2.
Amino acids play essential roles in various biological processes. In humans, most amino acids are present in the L-form; however, small amounts of D-amino acids also exist and have significant physiological roles, highlighting the importance of dietary intake from foods or drinks. In this study, we investigated the amino acid composition of the geoduck clam Panopea japonica, emphasizing its remarkably high D-alanine (D-Ala) content in the siphon tissue. The D-Ala content (6.99-14.2 mmol/100 g-wet) amounted to 91-94% of the total Ala, far exceeding that of other bivalves such as Tresus keenae (74%). Enzyme assays revealed alanine racemase and D-amino acid oxidase activities, suggesting active D-Ala biosynthesis and metabolism. The high concentrations of D-Ala enhance its value as a delicacy owing to its unique sweetness. This study provides new insights into the biosynthesis and metabolic characteristics of D-Ala in bivalves, highlighting its physiological and food ingredient significance.
氨基酸在各种生物过程中发挥着重要作用。在人类中，大多数氨基酸以L型存在；然而，少量的D型氨基酸也存在并且具有重要的生理作用，这突出了从食物或饮料中饮食摄入的重要性。在本研究中，我们调查了象拔蚌（Panopea japonica）的氨基酸组成，重点关注其虹吸管组织中显著高含量的D-丙氨酸（D-Ala）。D-Ala含量（6.99 - 14.2 mmol/100 g湿重）占总丙氨酸的91 - 94%，远远超过其他双壳类动物，如凯氏獭蛤（Tresus keenae）（74%）。酶活性测定显示了丙氨酸消旋酶和D-氨基酸氧化酶活性，表明存在活跃的D-Ala生物合成和代谢。高浓度的D-Ala因其独特的甜味而提升了其作为美味佳肴的价值。本研究为双壳类动物中D-Ala的生物合成和代谢特征提供了新的见解，突出了其生理和食品成分方面的重要性。
