Enxyme Kinetics I Flashcards
no matter how many substrate, is there a limit to Product
yes, there is
as [S] rises, what happens to Vo
Vo rises too but only at initial point
what is the reaction order for E+S»> ES
zero-order when [S]»_space; [E]
which is the rate limiting step between ES»>E+P and E + S»_space;>ES
ES»>E+P (k2)
Is V0 directly proportional to [S] always true
no, the enzyme differs
What is the theoretical speed limit at which an enzyme will not work any faster because it has reached it speed limit
Vmax
As [S] increases, Vo approaches Vmax true/false
true
As [S] increases, what happens to [ES]
it increases too
when does [ES] stop increasing
when [ES] =[E]T because [E]T=[ES] + [E]
Km is the
Michaelis constant
Km is related to
measure of the affinity of the enzyme for the substrate units in terms of concentration
Km is the combination of which constants
k2+k1/k1
Km is a measure of
ES binding or affinity
Small Km means
tight binding
large Km means
weak binding
Describe low [S] and high [S]
at low [S[, 1/2 Vmax =Km
at high [S] Vo= Vmax[S] /Km and Vo=Vmax
this is the # molecule of substrate converted to product by 1 enzyme molecule in 1 second (units of s-1)
Kcat
What is the rate-limiting step at saturation
Kcat
What tells you how good an enzyme is when they are working on 2 different substrates
specificity constant Vo= Kcat[E]T[S]/[S] + Km
what is Vo when [s] «_space;Km
Vo=Kcat [E]T[S]/Km
Kcat/Km tells you
how efficiently an enzyme
how is catalytic perfection achieved
when a reaction rate is diffusion-controlled (10^8-10^9)
When does Kcat/Km approach its “diffusion limit”
when the enzyme carries out catalysis every time a collision occurs between E and S
Whar are the modes in which subtrate binds to a enzynme
- Invoving a ternary complex
- No ternary complex
