Abstract：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.
Key words：Acid phosphatase;Ethanol;Activity;Conformation in solution
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