虎纹蛙皮肤分泌物抗氧化二肽——Gln/Lys-Met的纯化及鉴定

Purification and Characterization of Gln/Lys-Met, an Antioxidant Dipeptide from the Skin Secretion of Chinese Tiger Frog (Hoplobatrachus rugulosus)

目前已自青蛙皮肤分泌物中提取出多种属于"第三套抗氧化系统"的多肽,它们具有较强的抗氧化作用.本文从虎纹蛙皮肤分泌物中提取具有抗氧化活性的多肽物质,并检测其活性.利用电刺激虎纹蛙背部腺和耳后腺获得其皮肤分泌物,利用凝胶过滤色谱Sephadex G-50和反相高效液相色谱(reverse-phase high performance liquid chromatography,RP-HPLC)进行分离纯化.以2,2-二苯基-1-苦肼基(2,2-diphenyl-1-picrylhydrazyl,DPPH.)清除率为指标,测定多肽的抗氧化活性,经ESI-MS(electrospray ionization mass spectrometry)质谱测定该多肽的相对分子质量.结果显示,自虎纹蛙皮肤分泌物中获得一种具有抗氧化活性的二肽,其分子质量为0.277 kD,可能的氨基酸序列为Gln/Lys-Met.虎纹蛙皮肤分泌物中的该二肽是发挥抗氧化作用的重要组成部分.

Several antioxidant peptides isolated from the frog skin secretion were classified into the third antioxidant system. In this study, we purified a peptide with antioxidant activity from the skin secretion of Chinese Tiger Frog （Hoplobatrachus rugulosus）. The skin secretion was obtained by 9 V electrical stimulations of the dorsal skin glands from young adult frogs. The raw skin exudates were isolated by Sephadex G-50 size exclusion gel filtration and followed by reverse-phase high performance liquid chromatography （RP-HPLC）- The antioxidant activity of each fraction was determined by DPPH （2,2- diphenyl-l- picrylhydrazyl） radical scavenging assay. We obtained an antioxidant peptide of 0. 277 kD in molecular weight as shown by electrospray ionization mass spectrometry （ESI-MS）. The peptide sequence was indicated as Gln/Lys-Met. The result suggested that the peptide derived from the skin secretion of Chinese Tiger Frog was a potential molecule for antioxidation.