辣木叶蛋白质酶解产物的制备及其抗菌活性研究

为了研究辣木叶蛋白及其酶解产物的抗菌活性,利用碱提酸沉法提取辣木叶中的蛋白质,并分析其氨基酸组成;分别采用6种单酶和3种复合酶对辣木叶蛋白进行酶解,考察辣木叶蛋白及其酶解产物的抑菌活性,确定最佳蛋白酶。通过二倍稀释法,研究有效抑菌组分对不同菌的最小抑菌浓度(minimum inhibitory concentration,MIC)。结果显示:辣木叶蛋白提取率为32.67%±0.45%,必需氨基酸占氨基酸总量的39.27%。抑菌活性研究表明辣木叶蛋白仅对金黄色葡萄球菌显示抑菌活性,抑菌圈大小为(7.67±0.24) mm;胃蛋白酶结合胰蛋白酶分步酶解蛋白所得酶解产物抑菌能力均高于其他几种蛋白酶,酶解产物对化脓性链球菌的抑菌活性最强,抑菌圈大小为(10.83±0.62) mm,且其对金黄色葡萄球菌、单增李斯特菌及化脓性链球菌的MIC分别为5、10、2.5 mg/mL。说明辣木叶蛋白及其酶解产物均有抗菌活性,双酶酶解法制备的酶解产物具有较强的抑菌性及广抑菌谱。

Preparation of Enzymatic Hydrolysis Products from Moringa oleifera Leaves Protein and Its Antibacterial Activity

In order to study the antimicrobial activity of horseradish leaf protein and its enzymatic hydrolysate,the protein in Moringa oleifera leaf was extracted by alkali extraction and acid precipitation,and its amino acid composition was analyzed. Using six single enzymes and three complex enzymes to enzymatic hydrolysis protein,the antimicrobial activity of Moringa oleifera leaves protein and its enzymatic hydrolysates was investigated to determine the best protease. The minimal inhibitory concentration(MIC)of effective antibacterial components on different bacteria was studied by double broth dilution method. The results showed that the extraction rate of protein was 32.67%±0.45%,and essential amino acids account for 39.27% of total amino acids. The research of antibacterial activity showed that the protein of Moringa oleifera leaves showed antibacterial activity only against Staphylococcus aureus and the antimicrobial zone diameter was(7.67±0.24) mm. The antimicrobial activity of the enzymatic hydrolysate obtained by sequential hydrolysis with pepsin followed by trypsin was higher than that of other proteases. The enzymatic hydrolysate had the strongest antibacterial activity for Streptococcus pyogenes and the antimicrobial zone diameter was(10.83±0.62) mm. The minimum inhibitory concentration(MIC)were 5,10 and 2.5 mg/mL,respectively. The results showed that both the protein and its enzymatic hydrolysate of Moringa oleifera leaf had antimicrobial activity,and the enzymatic hydrolysate prepared by double enzymatic hydrolysis had strong antimicrobial activity and wide antimicrobial spectrum.