Thẻ ghi nhớ: Enzyme Action II: Quantitative Enzymology | Quizlet

closed

in a ______ system, all enzyme catalyzed rxns are bidirectional

assay

enzyme ____ involves 1) Mix S together with pH buffer solution 2) Add E 3) T optimum for E 4) Measure ^P vS 5) Calculate V

excess

S always present in ______ over E

fast

if excess S is not provided, rxn would be too ____ and the rxn rate cannot be measured

Beer's law

A=ECl, where E = molar extinction coefficient, l = thickness, C = concentration

kcat

____ is the Vmax an enzyme can produce normalized to quantity of E present

fES

___ is the fraction of E active sites occupied by substrate over the course of the enzyme assay

active

vo=Vmax * fES, this eqn says rxn rate is directly proportional to _____ site filling

S

when calculating kcat, Vmax is always expressed in terms of decrease of _

pH

kcat is a constant for each enzyme at a particular T and __

Km

__ is the [S] required to fill 50% of the active sites

Km

at __, vo=1/2Vmax

higher

the higher the kcat, the _____ (higher/lower) the efficiency of the enzyme

lower

the higher the Km, the ______ (higher/lower) the efficiency of the enzyme

is not

Vmax ____ (is / is not) a constant

irreversible

_______ inhibitors - covalently bond to enzyme, disrupts function of enzyme

reversible

______ inhibitors - binding driven by hydrophobic effect, H-bond replacement etc.

irreversible

______ inihibitors reduces [E], thus reduces Vmax

reversible

there are two types of ______ inhibitors: competitive and non-competitive

competitive

_______ inhibitors increase Km, reversible by adding excess substrate

non-competitive

_______ inhibitors decrease Vmax by binding onto sites non-covalently to sites other than the active site, distorting the E. can be reversed by removing inhibitors, which causes shift to the left of rxn Efree + Ifree -> EIcomplex