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

I.在海洋大型藻类提取物中发现了生物稀有的D-天冬氨酸。采用离子交换层析的方法从羊栖菜中分离出天冬氨酸，并在乙醇水中结晶。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。该晶体由等量的D和I异构体组成。游离D-天冬氨酸的存在方法相同(高效液相色谱法)。与绿藻和红藻中D-天冬氨酸的低浓度相比，褐藻的D-天冬氨酸含量普遍较高。特别是L天冬氨酸的Costaria costata、羊栖菜Hizikia fusiformis和条斑马尾藻Sargassum yezoensis。D-天冬氨酸含量随季节变化，秋末至初春含量较高，夏季含量较低。不同部位藻类的含量也不同，粘附根和主枝的含量普遍较高，叶片中的含量不到粘附根的一半。从8月份采集的花托中的含量与粘连根或主枝中的含量相似。根据这些结果，我们推测游离D-天冬氨酸可能在羊栖菜生长的早期阶段起重要作用。III.通过反相高效液相分析证实在各种海洋大型藻类中存在游离D-丙氨酸。在所研究的24种藻类中，有15种(54%)检测到游离D-丙氨酸的存在。褐藻属植物羊栖菜(Hizikia Fsiformis)、羊栖菜(Heterochordaria Abietina)、黑马尾藻(Sargassum Nigrifolum)的含量较高(分别为96、83和78nmol/g湿重)。D/L比值因藻种而异(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.