条斑紫菜R-藻红蛋白酶解物的制备及其抗氧化和肿瘤细胞增殖抑制活性

【目的】研究木瓜蛋白酶对条斑紫菜R-藻红蛋白的抗氧化性和肿瘤增殖抑制活性的影响。【方法】采用超声波破壁法提取条斑紫菜R-藻红蛋白，用DEAE柱层析法纯化后进行木瓜蛋白酶酶解，通过正交试验设计，以还原力A700为考察指标确定酶解反应的最佳工艺参数，进一步测定获得的R-藻红蛋白及其酶解物的还原力、清除羟自由基能力和对人肉瘤细胞U2O及人肝癌细胞HepG-2的肿瘤增殖抑制活性。【结果】R-藻红蛋白的最佳酶解工艺条件为：木瓜蛋白酶添加量25 000 U?g-1，pH 7.0，温度50℃，酶解时间4 h。在此条件下，R-藻红蛋白酶解物还原力为0.573，较未酶解的R-藻红蛋白提高了2.35倍；清除羟自由基能力为51.03%，较未酶解的R-藻红蛋白活性提高了3.22倍。随着浓度的增加，R-藻红蛋白及其酶解物对人肉瘤细胞U2O和人肝癌细胞HepG-2抑制生长作用增强。R-藻红蛋白对人肉瘤细胞U2O抑制作用的IC50值为2 431.32 μg?mL-1，其酶解物IC50值降低为1 271.46 μg?mL-1。R-藻红蛋白对肝癌细胞HepG-2抑制作用的IC50值为1 593.61 μg?mL-1，其酶解物IC50值降低为512.05 μg?mL-1。【结论】经木瓜蛋白酶酶解后，R-藻红蛋白酶解物具有较强的抗氧化和抑瘤活性。酶解技术可作为进一步提高R-藻红蛋白生物活性的有效手段。

Preparation of Enzymatic Hydrolysate of R-phycoerythrin from Porphyra yezoensis and Its Antioxidant and Tumor Cell Proliferation Inhibiting Activities

【Objective】The effect of enzymatic hydrolysis by papain on antioxidant and tumor cell proliferation inhibiting activities of R-phycoerythrin from Porphyra yezoensis was investigated.【Method】R-phycoerythrin of Porphyra yezoensis was extracted by ultrasonic cell wall breaking,and then purified by DEAE column chromatography.Orthogonal design was employed to obtain the optimal condition of enzymatic hydrolysis by determination of reducing powder A700 of their enzymatic hydrolysates.Subsequently,hydroxyl radical-scavenging ability and proliferation inhibiting activities of human sarcoma cancer cell U2O and liver cancer cell HepG-2 was compared as well.【Result】 The optimal enzymatic hydrolysis of R-phycoerythrin was selected at an amount of papain of 25 000 U.g-1,pH 7.0,a temperature of 50℃ and at a hydrolysis time of 4 h.Under the optimal treatment,the reducing powder of the R-phycoerythrin was raised up to 0.573,which was 2.35 times higher than that of untreated group.Hydroxyl radical-scavenging ability was 51.03%,which was 3.22 times higher than that of untreated group.With the concentrations increasing,the growth inhibition of R-phycoerythrin and their enzymatic hydrolysates against human sarcoma cancer cell U2O and liver cancer cell HepG-2 increased.The inhibition IC50values of R-phycoerythrin against human sarcoma cancer cell U2O was 2 431.32 μg.mL-1,which was decresed to 1 271.46 μg.mL-1 by enzymatic hydrolysates.The inhibition IC50values of R-phycoerythrin against liver cancer cell HepG-2 was 1 593.61 μg.mL-1,which was decresed to 512.05 μg.mL-1 by enzymatic hydrolysates.【Conclusion】The enzymatic hydrolysate of R-phycoerythrin by papain exhibited excellent antioxidant and antitumor activities,which proved that enzymatic hydrolysis could be an effective technology for further increasing the bioactivities of R-phycoerythrin.