木瓜蛋白酶制备广昌白莲降血压活性肽的研究

Research of the Nelumbo nucifera Gaerta antihypertensive peptides hydrolyzed by papain

为探讨木瓜蛋白酶对广昌白莲蛋白的水解特性及所获多肽的降血压活性,以广昌白莲蛋白为原料,以水解度（hydrolysis degree,DH）为指标,选用木瓜蛋白酶水解白莲蛋白获得多肽,通过测定多肽对血管紧张素转换酶（angiotensin converting enzyme,ACE）的抑制活性,得到广昌白莲ACE抑制活性肽。通过正交实验L_（12）（3~4）因素水平实验法确定木瓜蛋白酶水解白莲的最优条件为pH6.5,温度55℃,底物浓度5%,酶浓度8%。由极差值R可知各因素的主次关系是温度〉pH〉底物浓度〉酶浓度。对不同水解度下的多肽进行了降血压活性的研究,结果表明,ACE抑制率与水解度呈正相关。对多肽进行大孔吸附树脂静态乙醇分级洗脱后测定降血压活性,结果表明,经25%乙醇洗脱后,多肽降血压活性最高,为55.78%,其IC_（50）为0.045mg/mL。

To explore the Nelumbo nucifera Gaerta protein hydrolysis characteristics and received antihypertensive activity polypeptide by papain ,Nelumbo nucifera Gaerta as the raw material,angiotensin converting enzyme （ACE） inhibition rate and hydrolysis degree（DH） were used as a measure indicator and treated by papain to obtain hypotensive activity peptides. By orthogonal test L12（34） factors that determined the papain hydrolysis of Nelumbo nucifera Gaerta which optimal combination was.pH value 6.0, hydrolysis temperature 55~C,substrate concentration 5% ,enzyme concentration of 8%. By the value of R,the relationship between primary and secondary of factors was temperature〉pH 〉substrate concentration 〉enzyme concentration. Research of hypotensive activity polypeptides in different hydrolysis degree,the results showed that ACE inhibition rate and hydrolysis degree in a linear relationship. Macroporous adsorption resin was uesd for polypeptide to determinat hypotensive activity showed that after 25% ethanol,the resulting polypeptides hypotensive activity highest 55.78%,and the IC50 was O.045mg/mL.