Department of Biology, Faculty of Science and Graduate School of Science and Technology, Niigata University, Niigata, 950-2181, Japan.
Amino Acids. 2012 Dec;43(6):2505-12. doi: 10.1007/s00726-012-1331-x. Epub 2012 May 31.
Parasitic lampreys are known to secrete proteins having anticoagulant and vasodilator activities from the buccal glands during feeding on their host's blood. However, small molecules in the secretion have never been explored in detail. We examined the secretion of Japanese liver lamprey (Lethenteron japonicum) for small molecules and found an intensely fluorescent substance upon gel filtration. After purification by anion-exchange chromatography and reversed-phase HPLC, structure of the compound was determined to be L-3-hydroxykynurenine O-sulfate by NMR- and UV-spectrometry, complemented with enzymatic and chemical degradation. In vertebrates, the sulfate ester of 3-hydroxykynurenine is a compound that has been regarded as a urinary metabolite of tryptophan but not reported from normal tissues to date. Although the function of this molecule in the buccal glands remains to be elucidated, it is remarkable that the same substance was described in 1960s from two species of blood-sucking insects, Rhodnius prolixus and Triatoma infestans, suggesting its potential role in blood-feeding.
寄生性七鳃鳗在吸食宿主血液时，从其口腔腺分泌具有抗凝和血管舒张活性的蛋白质。然而，分泌中的小分子物质从未被详细研究过。我们研究了日本七鳃鳗（Lethenteron japonicum）的分泌产物，发现凝胶过滤时有一个强烈荧光的物质。经阴离子交换层析和反相 HPLC 纯化后，通过 NMR 和 UV 光谱学确定该化合物的结构为 L-3-羟基犬尿氨酸 O-硫酸盐，并辅以酶和化学降解。在脊椎动物中，3-羟基犬尿氨酸的硫酸盐酯被认为是色氨酸的一种尿代谢物，但迄今为止尚未有报道从正常组织中得到。尽管该分子在口腔腺中的功能尚待阐明，但值得注意的是，在 20 世纪 60 年代从两种吸血昆虫，即 R. prolixus 和 T. infestans 中就已经描述了相同的物质，这表明它在吸血过程中可能具有潜在的作用。
