麦芽酸性磷酸酶与乙醇相互作用的谱学研究

应用荧光光谱、紫外差光谱等技术研究了麦芽酸性磷酸酶经乙醇变性后活力与分子构象的变化情况，同时应用Lineweaver-Burk双倒数作图法考察了乙醇对酶动力学性质的影响。结果表明，乙醇对酶活力及分子构象有较显著的影响。酶活力随乙醇浓度增大而直线下降，50％的乙醇对酶的抑制率达43．4％；变性后酶的紫外差光谱在213和234nm处出现正吸收峰，表明酶肽链发生变化，酶分子由有序结构变成无规则卷曲；酶内源荧光强度随乙醇浓度的提高而增强，酪氨酸、色氨酸残基微环境在乙醇作用下发生明显变化，表明酶活力的表现与酶分子构象的稳定性和完整性密切相关。乙醇对酶的抑制类型为反竞争抑制。

Spectroscopic Analysis of the Interaction of Ethanol and Acid Phosphatase from Wheat Germ

Conformational and activity changes of acid phosphatase from wheat germ in ethanol solutions of different concentrations were measured by fluorescence spectra and differential UV absorption spectra. The effect of ethanol on kinetics of acid phosphatase was determined by using the double reciprocal plot. The results indicate the ethanol has a significant effect on the activity and conformation of acid phosphatase. The activity of acid phosphatase decreased linearly with increasing the concentration of ethanol. Differential UV absorption spectra of the enzyme denatured in ethanol solutions showed two positive peaks at 213 and 234 nm, respectively. The peaks on the differential UV absorption spectra suggested that the conformation of enzyme molecule changed from orderly structure to out of order crispation. The fluorescence emission peak intensity of the enzyme gradually strengthened with increasing ethanol concentration, which is in concordance with the conformational change of the microenvironments of tyrosine and tryptophan residues. The results indicate that the expression of the enzyme activity correlates with the stability and integrity of the enzyme conformation to a great degree. Ethanol is uncompetitive inhibitor of acid phosphatase.