碱性蛋白酶酶解魔芋飞粉制备ACE抑制肽研究

Studies on the Preparation of ACE Inhibitory Peptides from Konjac Fly Powder by Alkaline Protease Enzymolysis

以水解度为指标,对碱性蛋白酶酶解魔芋飞粉蛋白条件进行优化;测定不同酶解阶段及不同分子质量魔芋多肽的ACE抑制活性,筛选具有高ACE抑制活性的降血压多肽。结果表明:在底物质量分数2.25%,加酶量3 500 U/(g底物),温度55℃,pH 7.82的条件下酶解270 min,酶解产物的ACE抑制率达到最大值94.6%,此时水解度9.97%,多肽得率12.26%;酶解液经浓缩、干燥得到的魔芋多肽粉呈淡黄色,多肽含量52.62%,粗蛋白含量62.30%;用葡聚糖凝胶G-25和葡聚糖凝胶G-15串联柱分离得到2个具有高ACE抑制活性的多肽组分,其分子质量分别为1 500和1 000 Da,半抑制质量浓度分别为0.12 mg/mL和0.088 mg/mL。

The condition for preparation of angiotensin-I-converting enzyme inhibitory peptides by hydrolyzing konjac fly powder protein with alkaline proteasc was optimized using hydrolysis degree as index. The effects of different phases of hydrolysis and different molecular weight on the angiotensin-I-Converting Enzyme（ACE） inhibitory activities were measured, the peptides with high ACE inhibitory activities were screened. The results showed that the optimum conditions of enzymolysis were substrate concentration 2.25%, temperature 55 ℃, enzyme concentration 3 500 U/g substrate, pH value 7.82, time 270 rain. Under the optimum conditions, the inhibitory rate on ACE was 94.6%, the degree of hydrolysis was 9.97%, their yield was 12.26%. Konjac peptides were yellow powder obtained by concentrating and drying enzymic trydro lyzate, and their was 52.62%, their content of crude protein was 62.30%. Konjac peptides separated by series connection of sephadexG-25 and sephadexG-15 obtained two high inhibitory activities components with molecular weight 1 500 Da and 1 000 Da, their IC50 values were 0.12 mg/mL and 0.088 mg/mL.