酶法水解和筛选蛋黄蛋白质中的药物前驱型降血压肽

Enzymatic Hydrolysis and Screening of Prodrug-type Angiotensin I-converting Enzyme Inhibitor from Chicken Egg Yolk

为了筛选鸡蛋蛋黄蛋白质的酶解产物中的药物前驱型降血压肽，将鸡蛋蛋黄蛋白质经超临界CO2-乙醇萃取脱脂和NaOH溶液脱磷处理，用12种蛋白酶在各自适宜的条件下进行酶解，采用HPLC分析各酶解产物对血管紧张素酶（ACE）的抑制活性（IC50），并对IC50较小的6种水解产物进行保温实验，筛选药物前驱型降血压肽。结果显示，12种酶解产物对ACE的IC50值在0．69mg·mL^-1～4．06mg·mL^-1；保温实验显示仅有酶L的酶解产物IC50值明显减小，即由1．19mg·mL^-1降至0．59mg·mL^-1，其他5种酶解产物的IC50值则保持不变或升高，表明酶L的酶解产物中含药物前驱型降血压肽。

In order to screen prodrug-type angiotensin I - converting enzyme （ACE） inhibitor, chicken egg yolk protein was degreased by supercritical extraction of carbon dioxide and ethanol followed by alkaline dephosphorylation, and then hydrolyzed separately by 12 types of protease to prepare antihypertensive peptides. Inhibition to ACE （IC50） of the hydrolysates was determined by HPLC. IC50values of the 12 hydrolysates are in the range of 0. 69 mg ·mL^-1 to 4. 06 mg · mL^-1, and the hydrolysate obtained by protease G has the lowest IC50 value. The stabilities against ACE of six hydrolysates having lower IC50 values were investigated by pre-incubation. The pre-incubation experiment shows that the IC50 values of 5 hydrolysates were not decreased in despite of pre-incubation with ACE, and they can be regarded as inhibitor and substrate type. Only the hydrolysate obtained by protease L showed that its IC50 value against ACE after pre-incubation（0. 59 mg ·ml^-1） is smaller than that before preincubation （1. 19 mg ·ml^-1） and can be regarded as a prodrug-type ACE inhibitor.