An Enzyme Mediating the Conversion of Zeatin to Dihydrozeatin in <i>Phaseolus</i> Embryos
作者:Ruth C. Martin、Machteld C. Mok、Gordon Shaw、David W. S. Mok
DOI:10.1104/pp.90.4.1630
日期:1989.8.1
chromatography. NADPH was the only cofactor required for enzyme activity, and the pH optimum was 7.5 to 8.0. The enzyme did not recognize compounds closely related to zeatin, such as ribosylzeatin, cls-zeatin, O-xylosylzeatin, N(6)-(Delta(2)-isopentenyl)adenine, or N(6)-(Delta(2)-isopentenyl)adenosine. No conversion of dihydrozeatin to zeatin by the enzyme was observed. Two forms of the reductase could
在未成熟的菜豆胚的可溶性部分中检测到催化玉米素转化为二氢玉米素的还原酶。该酶通过硫酸铵分级分离和亲和、凝胶过滤和阴离子交换层析进行部分纯化。NADPH 是酶活性所需的唯一辅因子,最适 pH 值为 7.5 至 8.0。该酶无法识别与玉米素密切相关的化合物,例如核糖基玉米素、cls-玉米素、O-木糖基玉米素、N(6)-(Delta(2)-异戊烯基)腺嘌呤或 N(6)-(Delta(2)-异戊烯基)腺苷。没有观察到二氢玉米素被酶转化为玉米素。两种形式的还原酶可以通过凝胶过滤或阴离子交换高效液相色谱分离。高分子量同工酶 (M(r) 55,000 +/- 5, 000) 作为阴离子交换柱的第二个峰洗脱,而低分子量同工酶 (M(r) 25,000+/- 5000) 带负电荷较少。结果表明侧链减少发生在游离碱水平。此外,菜豆胚胎可用于检测玉米素特异性代谢酶。