Distribution and Physiological Function of D-Amino Acids on Marine Algae

1 .在大型海藻的提取物中发现了生物学上罕见的d -天冬氨酸。采用离子交换色谱法从梭形Hizikia fususiformis褐藻中分离出dl -天冬氨酸，并在乙醇水溶液中结晶。采用旋光色散分析和反相高效液相色谱分析对其进行了表征。晶体由等量的D和I异构体组成。用HPLC法测定游离d -天冬氨酸的含量。一般来说，藻门含有高浓度的d -天冬氨酸，而绿藻门和红藻门含有较低的d -天冬氨酸。特别是在costatia costata， Hizikia fususiformis和马尾藻yezoensis中，属于l -天冬氨酸。测定了不同季节、不同部位的梭形Hizikia fususiformis海藻中d -天冬氨酸的含量。d -天冬氨酸含量随季节变化而变化；深秋至早春高，夏季低。不同部位的藻类含量也不同；粘着根和主枝的含量普遍较高，叶片的含量不到粘着根的一半。从8月样品中获得的容器中含量与粘附根或主干中的含量相近。由此，我们推测游离d -丙氨酸可能在梭形Hizikia fusisformis的早期生长中起重要作用。iii .通过反相HPLC分析证实了游离d -丙氨酸在各种海洋大型藻类中的存在。在被检测的24种藻类中，有15种（54%）存在游离d -丙氨酸。褐藻中的梭形Hizikia fususiformis、abietina异脊索菌（Heterochordaria abietina）和黑尾马尾藻（Sargassum nigrifolium）含量最高，分别为96、83和78nmol/g wet wt.)。D/L比值在不同藻类中存在差异（0.03 ~ 0.49），D-丙氨酸含量与D/L比值无相关性。

I.The biologically rare D-aspartate was found in extracts of marine macroalgae. DL-Aspartate was isolated from the Phaeophyta, Hizikia fusiformis, By ion-exchange chromatography, and crystallized from aqueous ethanol. It was characterized by optical-rotatory-dispersion analysis and reversed phase HPLC analysis. The crystal consisted of equal amounts of D and I isomers. The presence of free D-aspartate was same method (HPLC) . Generally, Phaeophyta contained a high concentration of D-aspartate in contrast with the low concentration in Chlorophyta and Rhodophyta. Particularly in Costaria costata, Hizikia fusiformis and Sargassum yezoensis, belonging to those of L-aspartate.II.D-Aspartate content in marine alga, Hizikia fusiformis, was determined in various seasons and different parts of the alga. D-Aspartate content varied seasonally ; it was high from late autumn to early spring and low in summer. The content also differed among various parts of the alga ; it was generally high in the adhesive root and main branch, and that in the blade was less than half that in the adhesive root. The content in the receptacle which was obtained from August sample was showed a level similar to that in the adhesive root or the main branch. From these results, we have assumed that free D-aspartate might play important roles in the early stage of growth of Hizikia fusiformis.III.Occurrence of free D-alanine was verified in various marine macroalgae by the reversedphase HPLC analysis. The presence of free D-alanine was detected in 15species (54%) out of the total of 24 species of algae examined. The content was high in Hizikia fusiformis, Heterochordaria abietina, Sargassum nigrifolium of Phaeophyta (96,83 and 78nmol/g wet wt., respectively) . The ratio of D/L was different among algae species (0.03-0.49) , and there was no correlation between D-alanine content and D/L ratio.