Distribution of D-Amino acids in Aquatic Animals

D-氨基酸通常被认为是天然的奇物。然而，最近的研究表明，一些D-氨基酸在微生物、植物和高等动物中分布相当广泛。本研究从5门（软体动物门、节肢动物门、棘皮动物门、原脊索动物门和脊椎动物门）37种动物的组织中提取了80%乙醇提取物，并对提取物的理化性质进行了研究。以两种不同的方式测定提取物中D-丙氨酸的浓度：1）通过氨基酸自动分析仪测量在与D-氨基酸氧化酶（EC www.example.com）孵育之前和之后提取物中的丙氨酸1.4.3.3，和2）通过气相色谱法在手性Val毛细管柱上分析丙氨酸的三氟乙酰基1-丙基衍生物。（150-820毫克，D-丙氨酸的浓度以每100克组织的毫克数表示。）在一些海洋双壳类动物的肌肉中检测到， ...更多信息 而对日本蛤、布氏沙蚕、虾夷扇贝、栉孔扇贝和牡蛎等海洋双壳贝类的肌肉无明显影响。在所有含D-丙氨酸的物质中，D-丙氨酸的浓度远高于L-异构体的浓度。41毫克的D-丙氨酸也被发现在一个半咸的双壳贝类Corbicula leana的软的部分。值得注意的是，含有D-丙氨酸的双壳类属于异齿目，而缺乏D-丙氨酸的双壳类属于翼形目。在腹足类和头足类中没有检测到可测量量的D-丙氨酸。在所分析的所有甲壳类动物的肌肉中，都发现了D-丙氨酸，尽管D-丙氨酸与总丙氨酸的浓度比（D/D+L）在0.3和0.4之间，但D-丙氨酸的水平是可变的，从美洲蟹的10 mg到中华绒螯蟹的260 mg不等。在两种海胆的生殖腺中均检测到了大量的氨基酸，D/D+L比值分别为0.72和0.47，分别为90 mg和170 mg。海鞘、罗氏盐萼海鞘和5种鱼类的肌肉不含D-丙氨酸。少

D-amino acids are generally viewed as natural oddities. However, recent investigations show a rather wide distribution of some D-amino acids in microbes, plants and higher animals. The present studies were planned to accumulate more information on the distribution of D-enantiomer of alanine in aquatic animals.Eighty percent ethanol extracts were prepared from tissues of 37 species in 5 phyla (Mollusca, Arthropoda, Echinodermata, Prochordata, and Vertebrata). The concentration of D-alanine in the extracts was determined in two different ways: 1) measuring alanine in the extract before and after incubation with D-amino acid oxidase (EC 1.4.3.3) by an amino acid autoanalyzer and 2) analyzing as trifluoroacetyl 1-propyl derivatives of alanine by gas chromatography on a capillary column of chiracil-Val.Significant amounts of D-alanine (150-820 mg, The concentration of D-alanine is expressed in terms of mg per 100 g of tissue.) were detected in the muscles of some marine bivalves such as Mac … More tra chinensis, Spisura sachalinensis, Tresus keenae, Peronidia venulosa, and Meretrix lusoria but not in the muscles of marine bivalves such as Amusium Japonicum, Scapharca broughtonii, Patinopecten yessoensis, Atrina pectinata, and Ostrea edulis. In all the D-alanine-containing species, the concentration of D-alanine was much higher than that of L-isomer. Forty one mg of D-alanine was also found in the soft part of a brackish bivalve Corbicula leana. It is noteworthy that D-alanine-containing bivalves belong to the order Heterodonta and D-alanine-lacking bivalves to the order Pteriomorphia. No measurable quantity of D- alanine could be detected in gastropods and cephalopods. In the muscles of all the crustacean species analyzed, D-alanine was found. The level of the amino acid was variable, ranging from 10 mg in Homarus americanus to 260 mg in Eriocheir sinensis, although concentration ratio of D-alanine to total alanine (D/D+L) was between 0.3 and 0.4. Sizable amount of the amino acid was detected in the gonad of both species of sea urchins Hemicentrotus pulcherrimus (90 mg) and Anthrocidaris crassispina (170 mg) and their D/D+L ratios were 0.72 and 0.47, respectively. The muscle of ascidian Halocynthia roretzi and five species of fishes did not contain D-alanine. Less