Enzyme kinetics
Terms
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- V= d[P] /dt is also what?
- V= -d[S]/dt
- With decreasing [S] and increasing [P] , what wil be lost with time of reaction?
- linearity, in some cases P may inhibit E at higher concentrations.
- All E in the form of ES is what?
- Saturated
- When saturation is at high [S] increasing the [S] doesn't do what?
- increase the rate of reaction any further
- The velocity obtained at saturating [S] is what?
- the maximum velocity (Vmax)
- What is Michaelis's constant?
- [S] is 1/2 the Vmax. The term is called the Km
- What units are Km expressed in?
- moles/liter or mg/ml
- V=Vmax[S]/[S]+Km is also what?
-
Km=[S](Vmax-V)/V
so when, 2V=Vmax, Km=[S] - Km is sometimes associated with what?
- the strength of binding of the substrate for the enzyme.
- A substance with low dissociation rate is what type of affinity?
- higher affinity
- A substrate with low dissociation rate (high affinity)for the enzyme would reach what?
- half-maximal velocity at lower [S]
- A turnover number of enzyme reactions is what?
- Kcat
- The larger the Kcat the more often what happens on the surface of the enzyme?
- catalytic events
-
Units of Kcat are per what?
What does Kcat measure? -
per seconds, that is (s^-1)
measures number of substrate molecules turned over per enzyme per second. Values range from chymotypsin (0.1) to carbonic anhydrase (100,000). - The Kcat/Km determines the efficency of the enzyme-mediated reaction by giving what?
- The percentage of the effective collisions.
-
True or False
Some enzymes approach the theoretical limit where close to every collision result in catalysis. - True.
- Cells far from the thermodynamic equilibrium are in what state?
- The steady state.
- A dead cell is at what?
- equilibrium