本研究以Neutrase 0.8 L对酪蛋白进行水解，水解后的酪蛋白（HC）分别导入外源性氨基酸苯丙氨酸、组氨酸与脯氨酸进行类蛋白反应。所得的修饰产物（HCPHE、HCHIS和HCPRO）体外的DPPH?清除活性，羟自由基清除能力和还原能力与HC相比最大可分别提高30.51%、45.83%和42.81%（p<0.05）。HUPVC与修饰产物单独预孵育24 h后经300 μmol/L H2O2氧化损伤考察修饰产物对HUPVC的保护作用，CCK-8法测定细胞存活率结果表明修饰产物高剂量组的细胞成活率分别高于HC组7.86%、5.21%和10.52%（p<0.05），与茶多酚（TP）给药组无明显差异（p>0.05），并存在剂量依赖关系。与氧化损伤模型组相比，HCPHE、HCHIS和HCPRO可有效降低LDH渗出率，MDA生成量，SOD活力，降低效果强于同浓度的HC组，与此同时可使GSH-Rd，CAT的活力显著增强，然而细胞内GSH的含量变化不明显。综上所述，三种类蛋白反应修饰产物对H2O2诱导的HUPVC损伤具有很好的保护作用，且保护效果高于HC。

Casein was hydrolyzed by neutrase (0.8 L), and then the hydrolyzed casein (HC) was modified with phenylalanine (PHE), histidine (HIS), and proline (PRO) through plastein reaction. In vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH?) radical-scavenging abilities, hydroxyl radical-scavenging abilities, and reducing powers of the corresponding products (HCPHE, HCHIS, and HCPRO) were significantly higher than those of HC by 42.81%, 45.83%, and 30.51%, respectively (p<0.05). The modified products (HCPHE, HCHIS, and HCPRO) were incubated with human umbilical vein endothelial cells (HUVECs) for 24 h, and the protective effect of the modified products was evaluated after the HUVECs were injured using 300 μmol/L H2O2. Cell viability was measured using the CCK-8 method. The results showed that the cell viability of the groups treated with a high dose of HCPHE, HCHIS, or HCPRO was significantly higher than that of the group treated with HC by 7.86%, 5.21%, or 10.52% (p<0.05), respectively, and there was no significant difference between the high dose group and the group treated with tea polyphenols (TP) (p>0.05); furthermore, the relationship was dose-dependent. HCPHE, HCHIS, and HCPRO effectively decreased the leakage of lactate dehydrogenase (LDH), malondialdehyde (MDA) content, and superoxide dismutase (SOD) activity, compared with the HC group at the same concentration. Furthermore, HCPHE, HCHIS, and HCPRO significantly enhanced the activities of glutathione reductase (GSH-Rd) and catalase (CAT), while the change in the content of glutathione (GSH) in the cells did not significantly change. The study showed that HCPHE, HCHIS, and HCPRO had a good protective effect on H2O2-induced injury in HUVECs, with the protective effect being better than that of HC.

国家自然科学基金项目（31201337）