10. Enzymes Flashcards
Compounds, usually organic in nature, required by some enzymes before they will catalyze reactions
Coenzyme
A non-protein molecule, organic or inorganic that may be needed for enzyme function
Are ions that induce the necessary configuration for proper binding to the substrate
Cofactor
3 defining characteristics of enzymes
- Not consumed or permanently altered during the rxn
- Only small amounts required b/c re-used
- Accelerate speed at which a chemical rxn reaches equilibrium, but doesn’t alter equilibrium constant
What is an isoenzyme
Enzymes that catalyze the same rxn but have different structural and biochemical properties
2 of the most common isoenzymes
- Creatine kinase (CK)
- Lactate dehydrogenase (LD)
An organic cofactor bound tightly (covalently and permanently) to the apoenzyme
Prosthetic group
What is an apoenzyme
Heat-labile protein of the enzyme which requires a coenzyme for full catalytic activity
Class of enzyme:
Transfer of functional groups (other than hydrogen) between 2 substrates
Transferases
Class of enzymes:
Oxidation-reduction between 2 substrates
Oxidoreductases
These catalyze the hydrolytic (addition of water) cleavage of compounds
Hydrolases
Removal of groups from substrates without hydrolysis, to form double bonds
Lyases
Joining of 2 molecules coupled with hydrolysis of a pyrophosphate bond in ATP
Ligases
Define catalyst
A substance that accelerates the rate of a chemical rxn without becoming modified itself
Inorganic cofactors include metallic and non-metallic ions
May be essential for reaction or may just enhance the reaction rate
Activators
AKA complex enzyme (apoenzyme and cofactor/coenzyme)
Holoenzyme
