Enzyme Kinetics Flashcards
enzyme kinetics is the study of
the rate of formation of products from substrates in the presence of an enzyme
the reaction rate value is equal to
V = velocity
amount of product formed per unit time, in moles per seconds (mol/s), which depends on the concentration of substrate and enzyme
does the substrate or enzyme concentration fluctuate more in a reaction?
substrate concentration does
the reaction rate, V, is directly proportional to the substrate added when…
there is little substrate originally present
when there is so much substrate the active sites of enzyme are occupied thus addition of substrate does not affect the reaction rate
the term saturated refers to
when there’s so much substrate that every active site is continuously occupied and adding more doesn’t effect reaction rate and this is denoted as Vmax
michaelis constant (Km) indicates the substrate concentration when
the reaction rate is 1/2 of Vmax
a low Km of an enzyme-substrate means that
not very much substrate is require to get the reaction rate to half the maximum rate
thus enzyme has a high affinity for particular substrate
vice versa with high Km
cooperativity is a type of substrate binding to
multiple active site enzymes, in which the binding of one substrate molecule changes the binding of subsequent substrate molecule
when the binding of a substrate to one subunit increases the affinity of the other subunits of the substrate, this is
positive cooperativity
when the binding of a substrate to one subunit reduces the affinity of the other subunits for substrate, this is
negative cooperativity
zero order reaction rate means
there is not effect
first order reaction rate means
the concentration is double and the rate is doubled
second order reaction rate means
the concentration is double and the rate is quadrupled
rate law expression is
rate = k[A]’[B]’
in an enzyme-catalyzed reaction, the substate is
a reactant
