文档介绍：Chapter 4
Microbial Metabolism
Metabolism
Breakdown pounds into simpler ones
Generally hydrolytic reactions (水解反应)
Exergonic (产能)
Building pounds from simpler ones
Involve dehydration synthesis reactions(脱水/缩合反应)
Endergonic (耗能)
Catabolism (分解代谢)
Anabolism (合成代谢)
Metabolism in perspective
Enzymes
Catabolism and anabolism are all mediated by enzymes, which are proteins produced by living cells that catalyze (催化) chemical reactions by lowering the activation energy (活化能) required to start a reaction
Enzymes have specificity (专一性)
Each enzyme catalyzes only one reaction
Enzymes are very efficient-increase reaction rate by 108-1010 times
Turnover number(周转数): maximum no. of substrate molecules converted to product per second (单位时间内转变成产物的底物摩尔数)
Enzymatic reaction
Sucrose
glucose
fructose
+
Sucrase 蔗糖酶
蔗糖
葡萄糖
果糖
ponents
脱辅基酶蛋白
辅酶
全酶
底物
Activation energy
Activation energy: amount of energy needed to disrupt stable molecule so that reaction can take place
底物
产物
能量水平
非酶促反应所需活化能
酶促反应所需活化能
Enzymatic reaction steps
1. Substrate approaches active site
2. Enzyme-plex forms
3. Substrate transformed into products
4. Products released
5. Enzyme recycled
活性位点
酶-底物复合体
Factors Affecting Enzyme Activity
1. Temp
2. pH
3. Substrate concentration
4. Inhibitors
Enzyme inhibitor action
Competitive
Inhibition
petitive
Inhibition
变象位点