Studies on the Accumulation Mechanism and Metabolism of D-Alanine in Aquatic Animals

近年来的研究表明，某些D-氨基酸在海洋动物中的分布相当广泛。本研究旨在积累更多关于D-丙氨酸对映体在水生动物体内分布的信息，在水生动物、腔肠动物、扁形动物、纽形动物和原索动物中未检测到D-丙氨酸。含有D-丙氨酸的物种属于古腹足目和中腹足目，软体动物门中的真鳃亚纲，节肢动物门中的十足目和棘皮动物门中的真棘亚纲，缺乏D-丙氨酸的物种属于新腹足目，软体动物门中的翼鳃亚纲和头足纲，节肢动物门中的胸足目和等足目，棘皮动物门中的真海星总科和海参总科。来自杂色鲍、头巾壳、大菱鲆、Manoplex echo、Charonia sauliae sauliae、脉红螺、普通章鱼、日本普通鱿鱼和ocellate河豚的丙氨酸消旋酶活性进行了检查，在两个方向（D-丙氨酸L-丙氨酸和L-丙氨酸D-丙氨酸）。大菱鲆中肠酶活性L-到D-方向为21.3 μmol/g湿组织/h，D-到L-方向为26.3 μ mol/g湿组织/h。在腹足类的其他物种的许多组织中，除了脉脉蛙外，丙氨酸消旋酶的活性在两个方向上都存在。在普通章鱼、日本普通鱿鱼和斑节河豚的肝脏和肾脏中发现了仅D-至-L方向的丙氨酸消旋酶活性，这些物种是D-丙氨酸缺乏的物种（仅存在L-丙氨酸）。

Recent investigations show rather wide distribution of some D-amino acids in marine animals. The present studies were planned to accumulate more information on the distribution of D-enantiomer of alanine in aquatic animals.No measurable D-alanine could be detected in Periphery, Coelenterata, Platyhelminthes, Nemertinea and Prochordata species. D-Alanine-containing species belong to the order Archaegastropoda and Mesogastropoda, the subclass Eulamellbranchia in the phyla, Mollusca, the order Decapoda in the phyla Arthropoda and the subclass Euechinoidea in the phyla Echinodermata and D-alanine lacking species to the order Neogastropoda, the subclass Pteriomorphia and the class Cephalopoda in the phyla Mollusca, the order thoracica and Isopoda in the phyla Arthropoda, the class Euasteroidea and Holothuroidea in the phyla Echinodermata.Crude supernatant from tissues of Haliotis diversi color diversicolor, turban shell, Tectus maximus, Manoplex echo, Charonia sauliae sauliae, Rapana venosa, common octopus, Japanese common squid and ocellate puffer was examined for alanine racemase activity in both direction (D-alanine to L-alanine and L-alanine to D-alanine). The activity in mid gut glad of T.maximus was 21.3 μmol of product formed g wet tissue/h in the L-to-D direction and 26.3 in the D-to-L direction. In many tissues of the other species in Gastropoda except R.venosa alanine racemase activity occurs in both direction. Alanine racemase activity in the only D-to-L direction is found in liver and kidney of common octopus, Japanese common squid and ocellate puffer, which are D-alanine-lacking species (only L-alanine is present).