Modulation of protein biophysical properties by chemical glycosylation: biochemical insights and biomedical implications

Glycosylation constitutes one of the most important posttranslational modifications employed by biological systems to modulate protein biophysical properties. Due to the direct biochemical and biomedical implications of achieving control over protein stability and function by chemical means, there has been great interest in recent years towards the development of chemical strategies for protein glycosylation. Since current knowledge about glycoprotein biophysics has been mainly derived from the study of naturally glycosylated proteins, chemical glycosylation provides novel insights into its mechanistic understanding by affording control over glycosylation parameters. This review presents a survey of the effects that natural and chemical glycosylation have on the fundamental biophysical properties of proteins (structure, dynamics, stability, and function). This is complemented by a mechanistic discussion of how glycans achieve such effects and discussion of the implications of employing chemical glycosylation as a tool to exert control over protein biophysical properties within biochemical and biomedical applications. Received 15 December 2006; received after revision 28 March 2007; accepted 25 April 2007     

间套种植对根系土壤酶及养分复合系统的影响研究

通过池栽试验研究了玉米∥蚕豆、玉米∥鹰咀豆及3种单作作物生长盛期的根系空间分布特征,以及不同种植模式对土壤酶活性、养分含量空间分布的影响。结果表明,玉米∥蚕豆和玉米∥鹰咀豆地上生物量较对照均有不同程度的提高;0cm～30cm土层中玉米∥蚕豆根干重占总根重的比例较单作对照高10 78%,玉米∥鹰咀豆较对照低5 78%;根密度在垂直方向上可划分为4个类型区,0cm～20cm为高密度区、20cm～40cm为中密度区、40cm～60cm为低密度区、60cm以下为稀密度区;土壤酶活性可划分为4个层次:亚活跃层(0cm～10cm)、活跃层(10cm～30cm)、过渡层(30cm～40cm)和稳定层(40cm以下);根密度与土壤pH、有机质含量、全磷含量、全氮含量、有效磷含量呈显著或极显著相关。表3,参3。     

生物酶在羊毛织物防毡缩工艺中的应用

将蛋白酶和转移酶E2进行复配，应用于羊毛织物防缩整理，探索了最佳复配方案和工艺条件，经复合酶处理过的羊毛织物，其毡缩率可降低到1.26%，小于机可洗要求3％，应用扫描电镜观察了织物鳞片表层的破坏情况，进而了解酶作用的结果。     

富马酸烷·3-PG酯抗氧化和防霉性能

在对没食子酸丙酯 (PG)的抗氧化活性、富马酸酯的防霉活性进行分析和预测的基础上 ,对其分子结构进行改造 ,设计出一类新型化合物———富马酸烷·3-PG酯 .对五种目标产物进行抗氧化和防霉性能测试的结果表明 ,它们均同时具有与没食子酸丙酯相当的抗氧化性能和与富马酸二甲酯相当的防霉性能 ,打破了以往抗氧化剂和防霉剂需分别添加的传统     

Selectivity determinants of the aldose and aldehyde reductase inhibitor-binding sites

Aldose reductase and aldehyde reductase belong to the aldo-keto reductase superfamily of enzymes whose members are responsible for a wide variety of biological functions. Aldose reductase has been identified as the first enzyme involved in the polyol pathway of glucose metabolism which converts glucose into sorbitol. Glucose over-utilization through the polyol pathway has been linked to tissue-based pathologies associated with diabetes complications, which make the development of a potent aldose reductase inhibitor an obvious and attractive strategy to prevent or delay the onset and progression of the complications. Structural studies of aldose reductase and the homologous aldehyde reductase in complex with inhibitor were carried out to explain the difference in the potency of enzyme inhibition. The aim of this review is to provide a comprehensive summary of previous studies to aid the development of aldose reductase inhibitors that may have less toxicity problems than the currently available ones. Received 4 December 2006; received after revision 12 February 2007; accepted 20 April 2007     

酶与有机溶剂

本文阐述了酶在有机溶剂中存在的两种形式:通过表面活性剂聚集体在有机溶剂中的溶解和直接以固态酶的形式悬浮于有机溶剂中.讨论了反胶团(或w/o微乳浊液)系统在酶促反应、选择性提取蛋白质等领域的应用和固态酶悬浮于有机溶剂中的性质和特点,并展望了这些系统的发展前景.     

An enzyme immunoassay for mouse epidermal growth factor utilizing a liquid phase double-antibody system

Summary An enzyme immunoassay for mouse epidermal growth factor (EGF) involving a liquid phase double-antibody system was developed. The EGF--galactosidase conjugate prepared was stable for at least 8 months. By this method, EGF was detectable at a concentration as low as 20 pg per tube. The concentrations of EGF in various tissues of mice are also presented.This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

新型食品抗氧剂TBHQ的合成研究

在酸催化下,用对苯二酚和叔丁醇合成了叔丁基对苯二酚（ＴＢＨＱ）,它是一种食用新型抗氧剂。采用正交试验法探讨了各种反应因素对产率的影响。指出在物料比对苯二酚：叔丁醇：催化剂：溶剂为１∶１∶１．２∶２．９（ｍｏｌ）,反应温度为９０℃时,总共反应２．５小时,ＴＢＨＱ得率最高,可达５５％以上。     

“黑麦草-水稻”草田轮作系统的根际效应3.黑麦草根系对土壤生物性状的影响

在证实冬种黑麦草改善土壤理化性状的同时,研究对土壤生物性状的影响,结果表明：冬种黑麦草增加了土壤酶的活性,使脲酶活性提高了２．７５倍,转化酶活性提高了９２．６％;土壤微生物生物量增加１３倍;改善了土壤的微生物区系,细菌数量增加１．２倍,放线菌数量增加３．４倍,真菌数量下降了４４％．这些生物性状的改善,对提高地力和后作水稻的生长和发育具有良好的作用．     

FD-TRT耐热逆转录酶的特性分析

从嗜热细菌ＦＤ３００９中克隆并分离纯化得到的耐热逆转录酶（ＦＤ－ＴＲＴ）,逆转录反应在６５℃高温下进行,可克服常温逆转录酶的许多缺点,以酵母核糖体ｒＲＮＡ为模板,以与２５５和１８Ｓ ｒＲＮＡ匹配的寡聚脱氧核苷酸为引物,探明了ＦＤ－ＴＲＴ的最适反应条件： ２５ｍｍｏｌ／Ｌ Ｔｒｉｓ－ＨＣｌ（ｐＨ ８．５,２５℃）,２５ ｍｍｏｌ／Ｌ（ＮＨ４）２ＳＯ４,２ ｍｍｏｌ／Ｌ ＭｎＣｌ２,１００ μｇ／ｍｌ明胶．５ ｕｎｉｔ ＲＮａｓｉｎ,２５０ ｍｍｏｌ／Ｌ ４种 ｄＮＴＰ, １μＣｉ３ Ｈ－ｄＣＴＰ, １２ｕｇ ＲＮＡ,２５ ｐｍｏｌ引物,并在此条件下测得 ＦＤ－ＴＲＴ和 Ｔａｑ ＤＮＡ 聚合酶逆转录活力与聚合酶活力的相对比值分别为０．０５６,０．００４５．