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(一)乙醇能够使多酚氧化酶接触儿茶酚及焦性没食子酸氧化的活力提高,在50%乙醇溶液中,以儿茶酚为底料时,多酚氧化酶的活力比没有乙醇存在时的活力高出一倍以上。(二)50%的乙醇不能使多酚氧化酶接触其他双酚衍生物氧化的活力提高,相反地却有抑制作用。(三)无论有无抗坏血酸的存在,50%乙醇对多酚氧化酶活力的提高程度是一样的,在有一定量的抗坏血酸的存在下,多酚氧化酶对儿茶酚的 Michaelis 常数(25℃)在水溶液及50%乙醇溶液中各为0.072×10~(-3)M 及0.49×10~(-3)M。(四)乙醇的存在,并不影响多酚氧化酶氧化儿茶酚作用时氧气被完全还原为水的作用。无论乙醇存在与否,每一分子底料的氧化,都消耗一个氧原子。(五)其他水溶性有机溶剂对多酚氧化酶氧化儿茶酚活力的影响不同,如甲醇、异丙醇、叔丁醇、丙酮等能使酶活力提高;但1,4-二氧己圜、乙二醇、甘油等则有抑制作用。50%丙酮能使酶活力提高约3倍。
(A) ethanol can make polyphenol oxidase contact catechol and pyrogallol oxidation increased vitality, in 50% ethanol solution to catechol as a substrate, the activity of polyphenol oxidase than the absence of ethanol When the vitality more than doubled. (B) 50% ethanol can not make polyphenol oxidase contact with other bisphenol derivatives increased oxidation activity, on the contrary has inhibitory effect. (3) The Michaelis constant (25 ℃) of polyphenol oxidase to catechol in the presence of a certain amount of ascorbic acid was the same as that of 50% ethanol in the presence or absence of ascorbic acid. 0.072 × 10 -3 M and 0.49 × 10 -3 M respectively in aqueous solution and 50% ethanol solution. (D) The presence of ethanol, does not affect the role of polyphenol oxidase catechol oxidation role is completely reduced to water. Regardless of the presence or absence of ethanol, the oxidation of the substrate at the end of each molecule consumes one oxygen atom. (E) Other water-soluble organic solvents on the activity of polyphenol oxidase catechol oxidation different, such as methanol, isopropanol, tert-butanol, acetone and so can make the enzyme activity; but 1,4-dioxane , Ethylene glycol, glycerol, etc. are inhibited. 50% acetone can increase the enzyme activity about 3 times.