Mechanisms of Enzymatic Catalysis Flashcards
How do enzymes increase the rate of chemical reactions?
By lowing the amount of free energy required (activation energy) to reach the transition state between the substrate and the product
What are the 6 types of enzymes and the chemical reactions they catalyze?
- ) Oxidoreductases
- ) Transferases
- ) Hydrolases
- ) Lyases
- ) Isomerases
- ) Ligases
Oxidoreductases
Type of enzyme that transfers electrons (hydride ions or H atoms)
A (reduced) + B (oxidized) A (oxidized) + B (reduced)
Transferases
Type of enzyme that catalyzes group transfer reactions
AB + C) (A + BC
Hydrolases
Type of enzyme that catalyzes hydrolysis reactions
AB + H2O AH + BOH
Lyases
Type of enzyme that adds additional group of double bonds or forms double bonds by the removal of groups
AXH-B A-X + B-H
Isomerases
Type of enzyme that transfers groups within molecules to yield isomers
AB-C C-AB
Ligases
Type of enzyme that forms C-C, C-S, C-O, and C-N bonds coupled to cleavage of ATP
A + B + ATP A-B + ADP + Pi
Cofactors
Non-protein compounds that are necessary for many enzymes to function by either participating directly in catalysis or serving as carriers
What are the two types of cofactors?
- ) Metal ions (positively charged): stabilize transiently formed negative charges on substrates, or by carrying electrons
- ) Coenzymes (organic molecules, many of which are nucleotide based): transiently carrying charges or chemical groups during enzymatic catalysis
What are the two types of coenzymes?
- ) Cosubstrates: transiently/loosely associated with an enzyme
- ) Prosthetic groups: very tightly or covalently bound to and enzyme
What role do vitamins play in enzyme reactions?
Many vitamins serve as essential Coenzymes
