Enzymes 1 Flashcards
Enzymes
Bio catalysts. Do not change after reaction. Increase rate of reaction
Types of enzymes
Oxido-reductase Transferase Hydrolase Lyase Isomerase Ligases
Transferase
Functional groups from one molecule to another
Hydrolase
Break C-N, C-O, and C-C bonds with water
Lyase
Same as hydrolase without water
Isomerase
Rearrange molecule with no change in formula
Ligase
Make C-N, C-O, and C-C
Cofactor
Inorganic ions unattached to enzyme, but needed for max activity
Coenzymes
Organic molecules that help in transfer of functional groups
Apoenzyme
Enzyme without cofactor
Holoenzyme
Enzyme with cofactor
Active site
Small part, contains specific amino acids.
Keq
K1/K2
Or P/S
Standard free energy change
Free energy when products and reactants at 1 mol.
Free energy of activation
Always positive, reduced by enzymes
Factors affecting enzyme activity
pH, temp, enzyme and substrate concentration
Michaelis Menton equation
V= Vmax(S)/(Km+S)
Km
Vmax/2
Line weaver-burk
X intercept- -1/Km
Y intercept- 1/Vmax
Effect of E in reaction rate
Velocity proportional to E. Does not affect Km
Irreversible inhibition
Covalently bonds and denatures enzyme
Competitive inhibition
Increases Km, binds at active site, and can be overcome by more substrate.
Non competitive inhibition
Does not bind active site and changes confirmation. lowers Vmax, Km unchanged.
Allosteric regulation
Binds to non active site. Enzymes need quaternary structure. Have sigmoidal plot. Often feedback inhibition
Mechanisms of catalysis
Proximity, strain, covalently, acid base
Isoenzymes
Catalyze same reaction, with different Km and Vmax. Diff activation energy.
