中间体

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。

Wesynthesized (2E, 6E)-farnesol 12 starting from compound 24 by three steps.The optical sesquiterpenoid 14 was synthesized starting from--citronellol with a 28% overall yield, and the absolute configuration of 14 wasinfered (3R, 7S)-3, 7, 11-trimethyl-10-oxododecanoic acid on the basis of thechirality of starting material and biogenic relation.

以手性--香茅醇为原料，经七步反应也合成了旋光活性的目标分子14，结合生源关系，推测天然产物14的立体结构为(3R，7S)-3，7，11-三甲基-10 氧代-十二碳酸；对手性中间体34经脱除羰基得到手性天然产物(3R.7RS)-六氢法呢醇13。

Dibromoaniline is an important organic intermediate for synthesis of pharmaceuticals , alkaloid and ferromagnetics.

2 ，6 二溴苯胺是重要的有机合成中间体，可用于合成医药、生物碱和铁磁体等。

Once we get the authentication from China government and put them into production, they will become a new flashing point of our business and help Fukang obtaining further development.

主要从事原料药、医药中间体、溴化物、热敏染料四大系列五十多个产品的开发、生产和销售。主导产品原料药TMP年生产能力达到1600吨，占国内市场份额的80%，占全球总产量的55%。

The key applications,various methods of preparing hexafluoroacetone ,which is an important intermediate for synthesizing organic fluoric materials,were reviewed.

对合成有机氟材料的重要中间体———六氟丙酮的制备研究进展情况及其应用进行了综述。

Synthesis of trifluoromethylbenzene by fluorination of trichloromethylbenzene with hydrogen fluoride was investigated.

三氟甲基苯是一种重要的有机化工中间体，广泛应用于医药农药染料等领域。

The central intermediate of the process is the four-way junction that links two DNA duplexes.

这一过程的核心中间体是一个四通路的结合点，连接着两个DNA双链。

Diethyl fumarate was synthesized with fumaric and alcohol as raw materials and sodium acid sulfate as catalyst.

富马酸二乙酯(又名反丁烯二酸二乙酯，Diethylfumarate，简称DEF)是一种用途广泛的有机合成中间体[1，2]。

Based on functional group transformation and C-C bond formation,this review focuses on the first-rate progress of the catalytic asymmetric reaction in China in recent years,especially its application in synthesis of chiral drugs and pharmaceutical intermediates.

本文从官能团的转换和碳硫键形成的角度概述了我国近年来在不对称催化反应领域的研究进展，特别是在手性药物及其中间体合成中的应用进展。

GAMP ICH Q7A Section 5.4 cont'd 5.46 Incidents related to computerized systems that could affect the quality of intermediates or APIs of the reliability of records or test results should be recorded and investigated.

GAMP ICH Q7A第5.4节 5.46 与计算机系统相关的偶发问题可以影响记录的可靠性和中间体或原料药的质量，这些偶发问题需要记录并调查。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。