a mathematical expression for the time-dependent profress of a reaction as a funtion of reactant concentration
rate constant (k)
The proprtionality constant between the velocity of a cemical reaction and the concentration(s) of the reactant(s)
ES complex
The enzyme-substrate complex, whose formation is a key component of the Michaelis-Menten model of enzyme action. Also known as the Mechaelis complex
k_{1}
k_{2}
the rate constant for the second step of a simple enzyme-catalyzed reaction that follows Michaelis-Menten kinetics that is the conversion of the ES complex to E + P
k_{-1}
the rate constant for the reverse reaction e.g. breakdown of the ES complex to E+S
steady state
a set of conditions in an open system under which the formation and degradation of individual components are balanced such that the system does not change over time
steady state assumption
a condition for the application of the Michaelis-Menten model to an enzymatic reaction, in which the concentration of the ES complex remains unchanged over the course of the reaction
K_{M}
for an enzyme that follows the Michaelis-Menten model, K_{M}= (k_{-1}+ k_{2})/k_{1 }, K_{M }is equal to the substrate concentration at which the reaction velocity is half-maximal
Michaelis-Menten equation
mathmatical expression that desribes the activity of an enzyme in terms of the substrate concentration [S], the enzyme maximal velocity (V_{max}) and its Michaelis constant K_{M}: v_{0}= V_{max}[S]/ (K_{M}+ [S])
v_{0}
initial velocity of an enzymatic reaction
V_{max}
maximal velocity of an enzymatic reaction
enzyme saturation
a state in which the substrate concentration is so high that essentially all the enzyme molecules are in the ES form.
k_{cat} (turnover number)
the catalytic constant for an enzymatic reaction, equivalent to the ratio of the macimal velocity (V_{max}) and the enzyme concentration ([E]_{T})
k_{cat}/K_{M}
the apparent second-order rate constant for an enzyme-catalyzed reaction; it is a measure of an ezyme's catalytic efficiency
diffusion controlled limit
the theoretical maximum rate of an enzymatic reaction in solution, about 10^{8 }to 10^{9 }M^{-1}s^{-1}
Which rate constant describes the conversion of substrate to product in Michaelis-Menten kinetics?