几种重组别藻蓝蛋白的抗氧化活性  

Antioxidant activity comparison of different recombinant allophycocyanins

作　　者：韩璐[1] 葛保胜[1] 林秀坤[1] 秦松[1] 

机构地区：[1]中国科学院海洋研究所实验海洋生物学重点实验室

出　　处：《海洋科学》2007年第8期71-75,共5页Marine Sciences

基　　金：国家863计划资助项目(2006AA090303);中国科学院知识创新项目(KZCX2-YW-209)

摘　　要：藻胆蛋白是某些藻类特有的捕光色素蛋白,其中天然别藻蓝蛋白、藻蓝蛋白的抗氧化活性已经被证明。实验以2,2-盐酸脒基丙烷(AAPH)为自由基生成者,应用藏红花素退色反应为检测清除氢过氧自由基的方法,探讨了在大肠杆菌(Escherichia coli)中表达并纯化的带有6×His(6×组氨酸)标签和带有麦芽糖结合蛋白(MBP)标签的重组别藻蓝蛋白及其α、β亚基的抗氧化活性。结果表明,带有His标签的6×Hisα-APC、6×Hisβ-APC和6×His-APC均显示出一定的清除氢过氧自由基的能力,其中6×Hisβ-APC清除氢过氧自由基的IC50值可达到27.2 mg/L,Ka/Kc(氢过氧自由基与重组别藻蓝蛋白和藏红花素反应的速度常数比)达到1.24,大于带有色素基团的天然APC清除氢过氧自由基能力(IC5057.5 mg/L);而带有MBP标签的重组别藻蓝蛋白亚基MBPα-APC和MBPβ-APC和MBP-APC(rAPC)则无明显的清除能力。结果首次证实了脱辅基蛋白具有清除氢过氧自由基能力,因而在天然藻胆蛋白中脱辅基蛋白是清除自由基的贡献者之一,这为进一步研究重组别藻蓝蛋白的抗肿瘤机理提供了线索。The apo-allophycocyanin and its subunits expressed in Escherichia coli in our lab were purified with amylose affinity column or Ni^＋ - chelating affinity column. Their peroxyl radical （generated by AAPH） scavenging properties were evaluated by competition kinetics of crocin bleaching. The results showed that only recombinant allophycocyanin fused with 6 His-tag and its a or β subunit can scavenge peroxyl radical success fully, and the separated β subunit had a higher inhibition effect on peroxyl radical than others, with an IC50 value of 27.2mg/L and the rate constant ratio of 1.24, higher than the native allophycocyanin with an IC50 value of 57.5mg/L. We also observed that recombinant allophycocyanin fused with MBP- tag and its a or β subunit had no remarkable scavenging ability on peroxyl radical. These results clearly suggested that apo-allophycocyanin is involved in the antioxidant and radical scavenging activity of allophycocyanin. The antioxidant activity may be partially responsible for the anti-tumor effect of the recombinant allophycocyanin.

关 键 词：重组别藻蓝蛋白 清除自由基 2 2-盐酸脒基丙烷(AAPH) 藏红花素 

分 类 号：Q51[生物学—生物化学]