必需基团

目的研究化学修饰剂对N乙酰氨基葡萄糖转移酶Ⅲ和Ⅴ活性的影响以探讨这两种酶的必需基团。

Objective : The effects of the chemical modifiers on N acetylglucosaminyltransferase ( GnT ) ⅲ and V activities were studied to learn the essential groups of the enzymes .

此外，巯基、羟基和咪唑基对3种GnT均为非必需基团。

In contrast , sulfhydryl , hydroxyl and imidazolyl groups were found to be non essential groups of the three GnTs .

用甘氨酸甲酯对抗冻多肽B的羧基进行了化学修饰的动力学研究，表明羧基为其活性功能团，其三个二次羧基中仅有一个是必需基团。

Kinetic studies on chemical modification of the carboxyl groups indicate that only one out of the three COOH side chains was found to be essential for the activity of AFP-B of Winters Flounder .

结论：蝮蛇神经毒素的氨基是必需基团。

Conclusion : Amino in the neurotoxin is an important radical .

木瓜蛋白酶的研究&Ⅲ.组氨酸及色氨酸残基为木瓜蛋白酶表现催化活性的必需基团

Studies on papain III. histidine and tryptophane residues as essential groups

文昌鱼碱性磷酸酶的必需基团研究

Studies on the Essential Groups of the Amphioxus Alkaline Phosphatase

化学修饰法研究进一步证明侧链羧基是酶的必需基团，并测定出酶活性必需的羧基数为一个。

These results showed that the ionizing group of the enzyme active center is the carboxyl group .

蛋白质功能基团的改变与其生物活力的关系&Ⅰ.用图解法求必需基团数并判断其性质

Relation between modification of functional groups of proteins and their biological activity I. a graphical method for the determination of the number and type of essential groups

表明Trp残基是MDL凝集活性所必需的基团，且位于MDL糖结合部位。

It indicated that Trp residues were essential for the activity of MDL and involved at carbohydrate - binding site .

体外活性评价结果表明，C-3位羧基并非是喹诺酮基本结构中产生抗菌、抗肿瘤作用所必需的基团。

The in vitro bioactive assay showed that 3 - carboxy group is not a necessary group for antibacterial activity and antitumor activity of quinolones .

初步认为，Ser，Lys和Trp残基为黄鳝碱性磷酸酶的必需功能基团，部分二硫键对保护酶的催化能力是必需的。

It is thus tentatively assumed that Ser , Lys and Trp residues are essential functional groups of AKP while partial disulfide bond is essential for the catalytic capacity of the protective enzyme .

D环不是紫杉醇必需的活性基团。

Four-member D-ring is not necessary to maintain activity of Taxol analogue .

多肽的合成即氨基酸的缩合，但由于氨基酸的自身特性，有很多活性基团，从而引起许多副反应的发生，所以合成多肽前必需用保护基团将其暂时封闭起来，使得反应能够顺利进行。

However , amino acids themselves have many active groups , which leads to many side reactions , then they must be temporarily closed by using protecting groups before peptide synthesis , so as to the reaction can be proceed smoothly .