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

最近的研究表明，一些D-氨基酸在海洋动物中的分布相当广泛。本研究旨在为水产动物体内D-丙氨酸对映体的分布积累更多的信息，在周边动物、腔肠动物、扁形蠕虫、线虫和前索动物中未检测到D-丙氨酸。含有D-丙氨酸的物种属于古足目和中腹足纲，软体动物门中的真足亚纲，节肢动物门的十足亚纲，棘皮亚纲的真足纲和缺乏D-丙氨酸的物种，软体动物门的新腹足纲、翼形亚纲和头足纲，节肢动物门的胸足亚纲和等足纲，真虾纲和海鞘亚纲对日本乌贼和河豚的丙氨酸外消旋酶活性进行了双向测定(D-丙氨酸到L-丙氨酸和L-丙氨酸到D-丙氨酸)。极大疟原虫中肠GREE的活性在L-D方向为21.3mmolg湿组织/h，在D-L方向为26.3mol.μ/h。在腹足纲其他物种的许多组织中，丙氨酸消旋酶的活性是双向的。D-丙氨酸缺乏的章鱼、乌贼和河豚的肝和肾中只有D-对L方向的丙氨酸外消旋酶活性(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).