生物化学（山东大学） biosynthesis of proteins 蛋白质的生物合成.pdf

生物化学 Chapter 10 蛋白质的生物合成 Chapter 10 蛋白质的生物合成 Biosynthesis of Proteins Biosynthesis of Proteins 翻译translation 转译或翻译 （translation ）：按照 转录产生的mRNA中的 信息，合成蛋白质的过 程。也称之为表达 (expression) 。 翻译translation Translation needs more than a hundred macromolecules: Translation Several figures: • 60 to 90 macromolecules for making up the protein- synthesizing machine ribosomes; • Over 20 enzymes for activating the amino acids; • Over 10 auxiliary (辅助的) proteins for the initiation, elongation and termination of the polypeptide chains; 翻译translation • Account for up to 90% of the chemical energy used by a cell for all biosynthetic reactions; • The molecules used for translation account for more than 35% of the cell’s dry weight; 35% • Proteins are synthesized with extremely high efficiency: a complete polypeptide chain of 100 residues is synthesized in 100 residues o about 5 seconds in an E.coli cells at 37 C. 5 seconds 第一节 遗传密码(Genetic codes) 1.1 遗传密码的证明与确立 遗传密码的破译(deciphering) Avery 证明了核酸是生物的遗传物质； 关系？ 生命活动的体现者是蛋白质 1.1 遗传密码单位的大小 数学计算 （物理学家Gamov，1954） 4种核苷酸 20种氨基酸 4 bases (A, C, G, and U) • 1 nucleotide code 4 amino acids • 2 nucleotide code 42 = 16 amino acids • 3 nucleotide code 43 = 64 amino acids The triplet code is the smallest that can have unique combinations fo