DEUTERLUM-XYLOSE METABOLISM BY CELL-FREE EXTRACTS OF PENICILLIUM-CHRYSOGENUM
DEUTERLUM-XYLOSE METABOLISM BY CELL-FREE EXTRACTS OF PENICILLIUM-CHRYSOGENUM
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DOI：
10.1016/0006-3002(59)90395-6
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发表时间：
1959-01-01
期刊：
影响因子：
--
通讯作者：
KNIGHT, SG
中科院分区：
文献类型：
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作者：
CHIANG, C;KNIGHT, SG
通过产黄青霉的无细胞提取物进行的D-木糖代谢的初始步骤涉及通过还原的三磷酸吡啶核苷酸（TPNH）将木糖还原为木糖醇，随后是二磷酸吡啶核苷酸（DPN）连接的木糖醇氧化为木酮糖。已分离并鉴定了酶促形成的产物木糖醇和木酮糖。催化木糖还原为木糖醇的酶，暂时命名为D-木糖还原酶，纯化倍数为粗提物的20倍;它是一种诱导型酶，对D-木糖具有相对特异性。D-木糖的Ks为0.09 [图片]，TPNH为2.2-10-5 [图片]。该酶在pH 7.2时具有近似最大活性。0.05[image]的氟化物和0.001[image]的锌是强抑制剂。对氯汞苯甲酸的抑制作用可被谷胱甘肽或半胱氨酸恢复。亚砷酸盐，氰化物，碘乙酸和Vernatide在0.01时没有影响[图片]，镁，钙，锰和吡啶二甲酸在0.001时也没有影响[图片]。
The initial steps of D-xylose metabolism by a cell-free extract of Penicillium chrysogenum involve the reduction of xylose to xylitol by reduced triphosphopyridine nucleotide (TPNH), followed by diphosphopyridine nucleotide (DPN)-linked oxidation of xylitol to xylulose. The enzymically formed products, xylitol and xylulose, have been isolated and identified. The enzyme which catalyzes the reduction of xylose to xylitol and is tentatively named D-xylose reductase, was purified 20-fold over the crude extract; it is an inducible enzyme and relatively specific to D-xylose. The Ks for D-xylose is 0.09 [image] and for TPNH, 2.2-10-5 [image]. The enzyme had approximately maximum activity at pH 7.2. Fluoride at 0.05[image] and zinc at 0.001[image] were strong inhibitors. The inhibition by p-chloromercuri-benzoic acid could be restored by glutathione or cysteine. There was no effect by arsenite, cyanide, iodoacetic acid and Versene at 0.01[image], as well as magnesium, calcium, manganese, and dipicolinic acid at 0.001[image].