初二地理上册复习题.doc.pptVIP

* * 五、肽与蛋白质的人工合成 （一）肽的人工合成 氨基和羧基的保护 羧基的活化 常用的缩合剂是O,O′-二环己基碳二亚(O,O′-dicyclohexyl-carbodiimide,DCC) （二）固相肽合成 Solid phase synthesis of a peptide. Tertiary butyloxycarbonyl chloride (tBocCl) is an excellent reagent for blocking amino groups of amino acids during organic synthesis. Dicyclohexylcarbodiimide (DCCD) is a powerful agent for activating carboxyl groups to condense with amino groups to form peptide bonds. The carboxyl group of the first amino acid (the carboxyl-terminal amino acid of the peptide to be synthesized) is attached to an insoluble resin particle (the aminoacyl-resin particle). The next amino acid, with its amino group blocked by a tBoc group and its carboxyl group activated with DCCD, is reacted with the aminoacylresin particle to form a peptide linkage, with elimination of DCCD as dicyclohexylurea. Acid treatment removes the N-terminal tBoc blocking group as the gaseous products CO2 and isobutylene, exposing the N-terminus of the dipeptide for another cycle of amino acid addition. The growing peptide chain is easily recovered after cyclic additions of amino acids simply by filtering or centrifuging the reaction mixture. Chemical synthesis of a peptide on an insoluble polymer support. The major breakthrough in this technology was provided by R. Bruce Merrifield in 1962. His innovation involved synthesizing a peptide while keeping it attached at one end to a solid support.Reactions (1) through (4) are necessary for the formation of each peptide bond. The 9-fluorenylmethoxycarbonyl (Fmoc) group (shaded blue) prevents unwanted reactions at the α-amino group of the residue (shaded red). Chemical synthesis proceeds from the carboxyl terminus to the amino terminus, the reverse of the direction of protein synthesis in vivo. 9-芴甲氧羰基 基本要求 1.掌握蛋白质的分类和功能多样性； 2.掌握肽的结构特点和基本性质； 3.熟悉蛋白质一级结构的测定方法； 4.掌握蛋白质一级结构与生物学功能的关系，熟悉有关的典型例子。 5.熟悉蛋白质人工合成的基本步骤。 作业题 第194页第1题； 第194页第2题； 第195页第3题； 第196页第10题； 习题书第66页第10，31，32，34，35题， 第5章 蛋白质的三维结构 一、研究蛋白质构象的方法 (一)X射线衍