Module 6 - 2 Flashcards
(29 cards)
What are Binding Effects/transition state stabilization?
Increased interaction of enzyme and substrate.
What is Transition State (TS) Stabilization?
Essence of catalysis is stabilization of the transition state.
How does the enzyme distort the substrate?
Forces it toward the transition state.
What is the active site complementary to?
Transition-state in shape and chemical character.
How tightly do enzymes bind their transition states compared to their substrates?
1010 to 1015 times more tightly.
What must the active site be to ensure specificity?
Similar enough to substrate.
What must the active site be to promote change?
Different enough from substrate.
What are Transition State Analogs?
Stable compounds resembling unstable transition states.
What are Competitive Inhibitors?
Molecules that bind to the active site of an enzyme.
What do Competitive Inhibitors resemble?
The substrate molecule.
What are the potential therapeutic applications of Transition State Analogs?
As competitive inhibitors.
What is Enzymatic Catalysis?
Enzyme acts upon substrate to promote formation of product.
What do active sites often contain?
Chemically reactive side chains.
What are the polar, ionizable side chains involved in chemical catalysis?
Asp, Glu, His, Cys, Tyr, Lys, Arg, and Ser.
What are the two commonly observed mechanisms of chemical catalysis?
Acid/base Catalysis and Covalent Catalysis.
Acid/base Catalysis and Covalent Catalysis.
Reaction acceleration achieved by catalytic transfer of a proton.
What can the side chains of some amino acids act as?
Either bases or acids.
What amino acid is often involved in acid/base catalysis?
Histidine.
What influences the pKa of a functional group?
Chemical microenvironment.
What is covalent catalysis?
Substrate is covalently bound to enzyme.
What is the mechanism of covalent catalysis?
It involves two steps: forming a covalent linkage to the enzyme and regenerating the free enzyme.
What is the role of functional groups of amino acids in acid/base catalysis?
They have different pKas within the active site which make them more suitable for acid/base catalysis.
What is sucrose phosphorylase?
An enzyme that catalyzes the conversion of sucrose to fructose and glucose-1-P.
What are the steps involved in sucrose phosphorylase reaction?
Step 1: Glucosyl residue is transferred to enzyme. Step 2: Glucose is transferred to phosphate.
