enzymes Flashcards
non eompetitive inhibitors
affect on km and vmax
binds at an allosteric site
affects v max
does not affect km
cannot be overcome by increasing substrate concentration
competitive inhibitors and affect on Km and Vmax
bind to active site
affects km
does not affect Vmax
can be overcome by increasing substrate concentration.
units of Km
values that gives a measure of the affinity of the enxyme for its substrate
units are mM
a low km = high affinity for substrate
high km is a low affinity for substrate
what is the transition state ?
a high energy intermediate that lies between substrate and products
define the action of an enzyme
they lower the activation energy
by stabilising the transition state
and they facilitate the formation of the transition state
what is an active site
where substrate binds and where the chemical reaction occurs
only a small part of enzyme
formed from amino acids at different places along primary sequence
clefts or crevices
complementary in shape to the substrate - bindin may induce changes - induced fit hypothesis
bound to enzyme with multiple weak bonds
how are substrate concentration and rate linked
with increased substrate conc - the greater the velocity
gives a rectanglular hyperbola graph shape
reaches a maximal rate
define vmax and km V
Vmax - is the maximal rate when all all enzyme active sites are saturated with substrate
Km - the substrate concentration that gives half the maximal velocity
what are the y and x intercepts on a lineweaver burk plot
y = 1/vmax x = -1/km
the lower more negative the x intercept - the lower the km - the higher the affinity
the lower the y intercept the greater the vmax
define 1 unit
the amount of enzyme that produces 1um of product / uses 1 um of substrate per minute
under standard conditions
give the standardised rate
per litre of serum of per gram of tissue
