Enzymes Flashcards
(46 cards)
Apoenzyme
an enzyme without a cofactor
Holoenzyme
complete catalytically active enzyme
Cofactors
small organic molecule derived from vitamins and called coenzymes and metals.
Metals
tightly bound coenzymes are called prosthetic groups
Free energy
the measure of useful energy
When can a reaction take place spontaneously?
only if G is negative
When can this reaction NOT take place spontaneously?
only if g is positive
The amino acid position is in the N-terminus
acetylation
The amino acid position is in the C-terminus
Amidation
Ser, Tyr
phosphorylation
Pro
hydroxylation
Tyr,Lys
Methylation
Ser, Thr
Palmitaylation
Ser, Thr, Tyr
Sulphination
What is the heart of enzyme catalysis
the stabilization of the transition state
What are some characteristics of an active site?
1) There is a 3-D Cleft
2) Small part of the total volume of the enzyme
3) Unique micro environment
4) Substrates bound to enzymes by multiple weak attractions
5) Binding specificity depends on precisely defined arrangements
Induced Fit Theory
Daniel Koshland Jr. states that the active sites of some enzymes assume shape that is complementary to substrate after substrate binds
Binding Energy
The free energy that is released when weak interaction between complementary enzymes and substrates are formed.
Kinetics
study of the rates of chemical reactions- enzyme catalyzed reactions
Velocity
the quantity of the reactant A that disappears
Rate Constant
the way velocity is directly related to concentration of A by constant K
First-order reaction
where V is directly proportional to the reactant concentration
Second-order reaction
reaction with 2 reactants
Pseudo-first -order reaction
if reactant B is more than reactant A, and if A is present in low concentrations, reactions will be first order with respect to A and will not depend on B.
