侧金盏花叶片中d-核糖-5-磷酸还原酶的部分纯化及特性分析
Partial Purification and Characterization of d-Ribose-5-phosphate Reductase from Adonis vernalis L. Leaves.
作者信息
Negm F B, Marlow G C
机构信息
Department of Floriculture and Ornamental Horticulture, Cornell University, Ithaca, New York 14853.
出版信息
Plant Physiol. 1985 Aug;78(4):758-61. doi: 10.1104/pp.78.4.758.
This study presents evidence for a new enzyme, d-ribose-5-P reductase, which catalyzes the reaction: d-ribose-5-P + NADPH + H(+) --> d-ribitol-5-P + NADP(+). The enzyme was isolated from Adonis vernalis L. leaves in 38% yield and was purified 71-fold. The reductase was NADPH specific and had a pH optimum in the range of 5.5 to 6.0. The Michaelis constant value for d-ribose-5-P reduction was 1.35 millimolar. The enzyme also reduced d-erythrose-4-P, d-erythrose, dl-glyceraldehyde, and the aromatic aldehyde 3-pyridinecarboxaldehyde. Hexoses, hexose phosphates, pentoses, and dihydroxyacetone did not serve as substrates. d-Ribose-5-P reductase is distinct from the other known ribitol synthesizing enzymes detected in bacteria and yeast, and may be responsible for ribitol synthesis in Adonis vernalis.
本研究提供了一种新酶——D-核糖-5-磷酸还原酶的证据，该酶催化反应：D-核糖-5-磷酸 + NADPH + H(+) → D-核糖醇-5-磷酸 + NADP(+)。该酶从侧金盏花叶片中分离得到，产率为38%，并被纯化了71倍。该还原酶对NADPH具有特异性，最适pH范围为5.5至6.0。D-核糖-5-磷酸还原反应的米氏常数为1.35毫摩尔。该酶还能还原D-赤藓糖-4-磷酸、D-赤藓糖、DL-甘油醛和芳香醛3-吡啶甲醛。己糖磷酸、戊糖和二羟基丙酮不作为底物。D-核糖-5-磷酸还原酶与在细菌和酵母中检测到的其他已知核糖醇合成酶不同，可能负责侧金盏花中核糖醇的合成。
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