查询词典 reductase

Hydroxysteroid dehydrogenase/carbonyl reductase ( 3α-HSD/CR,EC 1.1.1.50 ) from Comamonas testosteroni is an inducible enzyme which catalyzes the oxidation of androsterone with NAD+ to form androstanedione and NADH. 3α-HSD/CR was a member of the SDRs family, whose crystal structure had been solved by X-ray diffraction in 2000. The structure of 3α-HSD/CR is a homodimer which shows a typical pattern of Rossmann-fold structure consisting of βαβ units, and reaveals similarity with other members upon the SDRs family.

中文摘要 3α-Hydroxysteroid dehydrogenase/carbonyl reductase ( 3α-HSD/CR，EC 1.1.1.50 )是从Comamonas testosteroni菌体中分离而来的诱发性酵素，利用NAD+为辅因子，将受质androsterone氧化成androstanedione并伴随NADH的生成而完成催化反应。3α-HSD/CR是属於SDRs家族成员之一，其立体结构已经在2000年利用X-ray晶体绕射所解出。3α-HSD/CR在结构上为一同源双聚体，并和其它家族成员一样具有βαβ二级结构所叠合组成的Rossmann-fold特徵。

The nitrate reductase is an molybdenum enzyme, molybdenum cofactor is necessary for the activity of nitrate reductase.

所有的硝酸还原酶都是钼酶，需要有钼辅助因子的参与。

Guanosine monophosphate reductase catalyzes the NADPH-dependent reductive deamination of Guanosine monophosphate to inosine monophosphate .

鸟苷酸还原酶(guanosine monophosphate reductase，GMPR)(EC 1.6.6.8)主要催化鸟嘌呤核苷酸向次黄嘌呤核苷酸的转化：GMP+NADPH+2〓→IMP+〓+NADP〓。

On the basis of the kinetic equation of substrate reaction in the presence of urea or guanidine hydrochloride, all microscopic kinetic constants for the free enzyme and enzyme-substrate binary and ternary complexes have been determined. The results of the present studies indicate that:①In the presence of urea or guanidine hydrochloride, enzyme-substrate complexes lose their activity less rapidly than the free enzyme. Therefore, both substrates, NADPH and 7, 8-dihydrofolate, protect dihydrofolate reductase against inactivation.②The denaturation of dihydrofolate reductase by urea follows single-phase kinetics, and changes in enzyme activity and tertiary structure proceed simultaneously in the unfolding process, so it may be an"all or none"process.③The GdnHCl-induced unfolding of the dihydrofolate shows a biphasic transition, while the change in the enzyme activity is a single exponential process. The rate constant of inactivation is consistent with that of the fast conformational change. Therefore, the kinetic intermediate of protein unfolding should be a partially folded and inactive form.

我们根据在脲或盐酸胍存在下的底物反应动力学方程求得游离酶和酶底物二元、三元复合物的微观动力学常数，结果表明：①酶-底物二元、三元复合物的失活速度明显慢于游离酶，说明两个底物二氢叶酸和NADPH对酶的失活都具有一定程度的保护作用；②在脲作用下，酶的失活和构象变化均为单指数项过程，而且酶的活力丧失和三级结构变化是同时发生的，说明二氢叶酸还原酶的脲变性可能是一个"全或无"的两态过程；③在盐酸胍作用下，酶的构象变化为两相过程，而失活则是单指数项过程，酶分子构象变化的快相速度常数与失活速度常数基本一致，因此我们认为二氢叶酸还原酶的盐酸胍变性过程中存在一个没有活力、但仍具备一定空间结构的变性中间体。

Methods Tissue culture was used to study the cataractous lenses of rats induced by sodium selenite or galactose. At the early stage, the content of nonprotein sulfhydryl, protein sulfhydryl, non-soluble disulfide bond, malonaldehyde and the activities of glutathione peroxidase, glutathione reductase and glutathione-S-transferase were measured in the cataractous lenses, and they were compared with that of the normal lenses. Results The two kinds of material could all induce cataract in rats, sodium selenite being more potent.

采用器官培养方法，以不同浓度亚硒酸钠及半乳糖作用于晶状体，诱发大鼠晶状体形成白内障，在培养初期测定晶状体内非蛋白质巯基（nonprotein sulfhydryl， NP-SH、蛋白质巯基（protein sulfhydryl ，P-SH）和不溶性蛋白质二硫键的含量，脂类过氧化水平，以及与谷胱甘肽代谢有关的谷胱甘肽过氧化物酶(GSH peroxidase， GSH-PX)、谷胱甘肽还原酶(GSH reductase， GSSG-R)及谷胱甘肽硫转移酶(GSH S transferase， GSH-S)的活性。

These results indicated that the increasing of the nitrate reductase activity stimulated flower-bud to pass during physiological and moephological differentiation stage. The decreasing of nitrate reductase activity and the increasing of ammoniacal nitrogen content stimulated the plants to blossom.

表明硝酸还原酶活性在花芽生理分化期至形态分化期的升高有利于促进花芽的转化和形成；形态分化后期至初花期，硝酸还原酶活性的下降，氨态氮含量的上升有利于促进开花。

Four different catechin content cultivars were selected from our tea germplasm appraisal database to assay the gene expression level of the seven genes, flavonol synthase, dihydroflavonol-4-reductase, leucoanthocyanidin reductase, anthocyanidin synthase, etc, which were involved in the flavonoids biosynthesis. The result showed that, the DFR and LAR transcripts were expressed increased with the increasing of tea catechin contents. Nevertheless, the others did not show this tendency clearly.

利用半定量PCR技术检测总儿茶素含量不同的4个茶树品种中与类黄酮合成相关的黄酮醇合成酶、二氢黄酮醇－4-还原酶、无色花色素还原酶、花色素合成酶等7个基因的表达情况，结果表明DFR和LAR基因的表达量与茶树中总儿茶素含量呈一定的相关性，而其他基因则与其相关性不大。

Assimilatory nitrate reductase is a soluble, multiple center redox enzyme that catalyses the two-electron reduction of nitrate to nitrite using pyridine nucleotide as a electron donor.

植物中的硝酸盐还原酶(nitrate reductase，NR)作为限速酶，催化硝酸盐还原为亚硝酸盐，这一过程在氮代谢中处于关键地位，对植物生长发育、产量形成有重要影响。

NADP-Dependent Retinol Dehydrogenase/Reductase identified from rabbit liver cytosol is involved in oxidoreduction between retinol and retinal with high activity. Therefore, NRDR plays an important role in modulation of the retinoids and RA homeostasis.

辅酶Ⅱ依赖性视黄醇脱氢/还原酶NADP(H-Dependent Retinol Dehydrogenase /Reductase NRDR是黄东阳教授等从兔肝中发现并纯化的一种酶，具有很高的催化视黄醛和视黄醇之间氧化还原反应的活性，对体内类视黄醇和维甲酸的代谢平衡起着重要的调节作用。

Methods Male New Zealand white rabbits were exposed to pentavalent arsenate and trivalent arsenite 5 mg/L for 18 weeks, respectively. Levels of thioredoxin, protein and non-protein sulfhydryl and the activity of thioredoxin reductase and glutathione reductase in liver, and the levels of inorganic arsenic, monomethylarsonic acid and dimethylarsinic acid in blood, urine, and hair were measured after that.

家兔以自由饮水方式慢性暴露于无机3价砷及5价砷，18周后，测定肝脏组织中蛋白巯基、非蛋白巯基、硫氧还蛋白水平，以及硫氧还蛋白还原酶、谷胱甘肽还原酶活性，同时检测血、尿及毛发中无机砷及其代谢产物甲基砷和二甲基砷。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。