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首页> 外文期刊>The biochemical journal >Conversion of p-coumarate into caffeate by Streptomyces nigrifaciens. Purification and properties of the hydroxylating enzyme
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Conversion of p-coumarate into caffeate by Streptomyces nigrifaciens. Purification and properties of the hydroxylating enzyme

机译：用链霉菌硝化缩合将P-香豆素转化为咖啡因。羟基化酶的纯化和性质

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p1. An enzyme responsible for the conversion of ip/i-coumarate into caffeate was purified 97-fold from iStreptomyces nigrifaciens/i. The enzyme had a molecular weight of 18000 as determined by Sephadex G-100 gel filtration and was homogeneous on polyacrylamide-gel electrophoresis. 2. The preparation exhibited both ip/i-coumarate hydroxylase and caffeate oxidase activities. 3. Stoicheiometry of the reaction indicated a mono-oxygenase-mediated catalysis consuming 1mol of Osub2/sub/mol of substrate hydroxylated. 4. NADH, NADPH, tetrahydropteroylglutamate or ascorbate act as electron donors for the reaction, ascorbate being inhibitory at higher concentrations. 5. The optimum enzyme activity was at about pH7.7 and 40°C, with an activation energy of 39kJ/mol. 6. Monophenols such as ip/i-hydroxyphenylpropionate, ip/i-hydroxyphenylacetate, l-tyrosine and dl-ip/i-hydroxyphenyl-lactate were also hydroxylated by the preparation, in addition to ip/i-coumarate. 7. The enzyme was a copper protein having 0.38% copper in a bound form. 8. Thiol-group inhibitors did not affect the reaction. 9. The relationship of the enzyme to other hydroxylases is discussed./p
机译：> 1。纯化来自链霉菌Nigrifaciens的97倍，纯化了对咖啡因的转化为咖啡因的酶-carmate。通过Sephadex G-100凝胶过滤测定，酶的分子量为18000，并在聚丙烯酰胺 - 凝胶电泳上均匀。 2.制剂表现出 P - 酸盐酸盐酶和肉咖啡因氧化酶活性。 3.反应的化学表明表明单氧酶介导的催化催化催化1molO 2 /摩尔底物羟基化的。 4. NADH，NADPH，四氢钨酰谷氨酸或抗坏血酸作为反应的电子供体，抗坏血酸含量较高浓度。 5.最佳酶活性在约pH7.7和40℃下，具有39kJ / mol的活化能。 6.单苯酚如 p - 羟基苯基丙酸盐，钯，L-酪氨酸和DL- P - 羟基苯基乳酸盐也是羟基化的制备，除了 p - 加油站。 7.酶是铜蛋白质，铜蛋白质以染色形式为0.38％。 8.硫醇组抑制剂不影响反应。讨论了酶与其他羟基酶的关系。

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