Enzymes Reaction Activation without enzyme energy without enzyme Activation Reactant Reaction energy with enzyme with enzyme Initial energy level Final energy level Products Figure 5.2
Enzymes Figure 5.2
Enzymes Biological catalysts Specific for a chemical reaction;not used up in that reaction ·Apoenzyme:protein Cofactor:Nonprotein component Coenzyme:Organic cofactor Holoenzyme:Apoenzyme cofactor
• Biological catalysts • Specific for a chemical reaction; not used up in that reaction • Apoenzyme: protein • Cofactor: Nonprotein component • Coenzyme: Organic cofactor • Holoenzyme: Apoenzyme + cofactor Enzymes
Enz☑ymes Substrate Coenzyme Apoenzyme Cofactor Holoenzyme (protein portion), (nonprotein portion), (whole enzyme), inactive activator active Figure 5.3
Enzymes Figure 5.3
Important Coenzymes ·NADt 。NADP+ ·FAD 。Coenzyme A
• NAD+ • NADP+ • FAD • Coenzyme A Important Coenzymes
Enzymes The turnover number is generally 1-10,000 molecules per second. ubstrate Active site Products Enzyme Enzyme-substrate complex (a) Substrate Enzyme Enzyme Figure 5.4
• The turnover number is generally 1-10,000 molecules per second. Enzymes Figure 5.4