Berg·Tymoczko·Stryer Biochemistry Sixth Edition Chapter 9: Catalytic Strategies Copyright 2007 by W.H.Freeman and Company
Biochemistry Sixth Edition Chapter 9: Catalytic Strategies Copyright © 2007 by W. H. Freeman and Company Berg • Tymoczko • Stryer
Chess and enzymes have in common the use of strategy, consciously thought out in the game of chess and selected by evolution for the action of an enzyme. 酶和下棋有异曲同工之处： 下棋要精细考虑；酶作用的选择性进化。 Chapter 9Opener Biochemistry,Sixth Edition 2007 W.H.Freeman and Company The three amino acid residues at the right constitute a catalytic triad.催化三联体加入象棋中的皇后，不能有损
Chess and enzymes have in common the use of strategy, consciously thought out in the game of chess and selected by evolution for the action of an enzyme. 酶和下棋有异曲同工之处： 下棋要精细考虑；酶作用的选择性进化 The three amino acid residues at the right constitute a catalytic triad. 催化三联体加入象棋中的皇后，不能有损
Sources of the catalytic power and specificity of enzymes? 酶催化能力及特异性从何而来？ The catalytic strategies used by four classes of enzymes: 1.serine proteases:丝氨酸蛋白酶 2.carbonic anhydrases碳酸脱水酶 3.restriction endonucleases限制性核酸内切酶 4.Nucleotide Monophosphate Kinases:核苷单磷酸激酶 water to a substrate The mechanism of each enzyme was revealed through the use of incisive experimental probes机制清楚，实验可证明 protein structure determination (Chapter 3) site-directed mutagenesis (Chapter 5)
The catalytic strategies used by four classes of enzymes: 1. serine proteases丝氨酸蛋白酶 2. carbonic anhydrases碳酸脱水酶 3. restriction endonucleases限制性核酸内切酶 4. Nucleotide Monophosphate Kinases核苷单磷酸激酶 Sources of the catalytic power and specificity of enzymes? 酶催化能力及特异性从何而来？ The mechanism of each enzyme was revealed through the use of incisive experimental probes 机制清楚，实验可证明 - protein structure determination (Chapter 3) - site-directed mutagenesis (Chapter 5). water to a substrate
Strategies to solve a different problem解决催化反应面临的挑战 每类酶的催化机制能解决各种化学反应所面临的问题。 -Serine proteases丝氨酸蛋白酶：to promote a reaction that is almost immeasurably slow at neutral pH in the absence of a catalyst.pH 7.0 几乎不发生的反应（蛋白质水解）进行下去 -Carbonic anhydrasesi碳酸脱水酶：to achieve a high absolute rate of reaction,suitable for integration with other rapid physiological processes. 加速，以与其他快速生理过程融合 -Restriction endonucleases限制性核酸内切酶，to attain a high degree of specificity.实现酶切反应的高度特异性 -NMP kinases核苷单磷酸激酶：to transfer a phosphoryl group from AT P to a nucleotide and not to water.磷酸基团从ATP转移给另一个核苷酸（而 不会转移到水分子) Structural and mechanistic comparisons of enzyme action are thus the sources of insight into the evolutionary history of enzymes.In addition,our knowledge of catalytic strategies has been used to develop practical applications,including potent drugs
-Serine proteases丝氨酸蛋白酶: to promote a reaction that is almost immeasurably slow at neutral pH in the absence of a catalyst. 将pH 7.0 几乎不发生的反应(蛋白质水解）进行下去 -Carbonic anhydrases碳酸脱水酶: to achieve a high absolute rate of reaction, suitable for integration with other rapid physiological processes. 加速， 以与其他快速生理过程融合 -Restriction endonucleases限制性核酸内切酶, to attain a high degree of specificity.实现酶切反应的高度特异性 - NMP kinases核苷单磷酸激酶: to transfer a phosphoryl group from AT P to a nucleotide and not to water.磷酸基团从ATP转移给另一个核苷酸（而 不会转移到水分子） Strategies to solve a different problem 解决催化反应面临的挑战 Structural and mechanistic comparisons of enzyme action are thus the sources of insight into the evolutionary history of enzymes. In addition, our knowledge of catalytic strategies has been used to develop practical applications, including potent drugs. 每类酶的催化机制能解决各种化学反应所面临的问题
A few basic catalytic principles基本催化原理 Enzymatic catalysis begins with substrate binding. The binding energy结合能：a large number of weak interactions between the enzyme and the substrate.弱相互作用 The binding energy as serving two purposes: establishes substrate specificity Only the correct substrate can participate in the interactions increases catalytic efficiency the full complement of such interactions is formed only when the combination of enzyme and substrate is in the transition state. The binding energy can also promote structural changes in both the enzyme and the substrate that facilitate catalysis,a process referred to as induced fit
The binding energy结合能: a large number of weak interactions between the enzyme and the substrate. 弱相互作用 The binding energy as serving two purposes: - establishes substrate specificity Only the correct substrate can participate in the interactions - increases catalytic efficiency the full complement of such interactions is formed only when the combination of enzyme and substrate is in the transition state. A few basic catalytic principles 基本催化原理 The binding energy can also promote structural changes in both the enzyme and the substrate that facilitate catalysis, a process referred to as induced fit. Enzymatic catalysis begins with substrate binding