牦牛乳酪蛋白肽分离组分对DPP-4活性的抑制作用

Dipeptidyl peptidase-4 inhibitory activity of fractions obtained from yak milk casein-derived peptides

以牦牛乳酪蛋白为原料,研究牦牛乳酪蛋白水解产物及其分离组分对二肽基肽酶-4(DPP-4)活性的抑制作用。以木瓜蛋白酶水解牦牛乳酪蛋白,水解产物采用Sephadex G-25凝胶过滤色谱进行分离,以DPP-4抑制率为指标,分析水解产物和分离组分对DPP-4活性的抑制作用。结果表明,木瓜蛋白酶水解0.5 h获得的水解产物表现出最强的DPP-4抑制活性,抑制率可达(59.57±0.23)%,半抑制浓度(IC50)为0.67 mg/m L。经Sephadex G-25凝胶过滤分离将木瓜蛋白酶水解产物分成4个组分,其中第3个组分对DPP-4抑制作用最强,IC50值为0.583 mg/m L。研究结果表明,与牦牛乳酪蛋白相比,其水解产物的DPP-4抑制活性显著增强,经凝胶过滤色谱分离后的水解产物分离组分具有更强的DPP-4抑制活性。

The dipeptidyl peptidase-4 （DPP-4） inhibitory activity of hydrolysates and fractions derived from yak milk casein were investigated. Yak milk casein was hydrolyzed by papain and the obtained hydrolysates were separated with gel filtration chromatography on Sephadex G-25. The DPP-4 inhibition rate of hydrolysates and fractions was determined. Results showed that papain hydrolysate obtained at 0.5 h hydrolysis exhibited the highest inhibitory activity against DPP-4 [（53.95±1.57）% inhibition]. IC50 value of 0.67 mg/mL was obtained for the hydrolysate. The hydrolysate was fractionated into 4 fractions by gel filtration chromatography on Sephadex G-25 and fraction 3 showed the highest DPP-4 inhibitory activity with IC50 value of 0.583 mg/mL. The results suggest that hydrolyzed yak milk casein possesses potent DPP-4 inhibitory activity compared with yak milk casein and hydrolysates fractionated by gel filtration chromatography showed higher inhibitory activity on DPP-4.