乙醛对假丝酵母脂肪酶催化活性的影响

Effect of Acetaldehyde on Catalytic Activity of Candida Rugosa Lipase

采用紫外可见分光光度法和荧光发射光谱法研究了乙醛溶液对假丝酵母脂肪酶水解三油酸甘油酯的催化活性和构象的影响。结果表明,低浓度乙醛能提高酶的催化水解活力,当乙醛浓度为0.221 5 mmol/L时,酶活力提高了18.84%;高浓度乙醛对酶活力有抑制作用,当乙醛浓度为3.322 5 mmol/L时,酶活力降低了25.85%。低浓度乙醛使酶催化反应的最适p H向碱性方向偏移,紫外吸收光谱和荧光发射光谱均有显著增强和光谱峰偏移现象。动力学分析表明,加入乙醛后,酶的V_(max)增大,K_m减小。

The alteration of Candida rugosa lipase（CRL） activity and conformation were studied after pretreatment with acetaldehyde solutions at different concentrations by UV-vis spectroscopy and fluorescence emission spectroscopy. The results showed that the lipase activity increased in the presence of acetaldehyde at low concentration and the highest increasement was 18.84% when the acetaldehyde concentration was 0.221 5 mmol·L^-1.The lipase activity decreased in the presence of acetaldehyde at high concentration and the highest decreasement was 25.85% when the acetaldehyde concentration was 3.322 5 mmol·L^-1. The optimum p H value of the 1ipase in the presence of acetaldehyde increased by 0.5 compared to that in the absence of acetaldehyde. The UV absorption and fluorescence emission intensities of the lipase in the presence of acetaldehyde were enhanced markedly and the spectral peaks shifted conpared to the contrast. When CRL was treated with acetaldehyde, the Vmax increased while K_m value declined.