Final answer:
The steady state assumption in enzyme kinetics maintains that the formation and breakdown of the enzyme-substrate complex (ES) are balanced, resulting in a constant ES concentration during the reaction, under conditions where substrate is in excess over enzyme. This is a foundational concept in Michaelis-Menten kinetics.
Step-by-step explanation:
The steady state assumption in enzyme kinetics is critical for understanding how enzymes function under certain conditions where the enzyme concentration is kept constant while varying the substrate concentration. Two statements that correctly summarize the steady state assumption are:
The formation and deformation of ES (enzyme-substrate complex) are equal, which means that at the steady state, the rate at which the enzyme-substrate complex is formed is the same as the rate at which it breaks down into enzyme and product or reverts to enzyme and substrate.
The ES concentration stays steady, implying that despite ongoing reactions, the amount of enzyme-substrate complex remains constant over time.
These conditions lead to the Michaelis-Menten kinetics that describe how the velocity of an enzyme-catalyzed reaction changes with varying substrate concentrations when substrate is in excess over enzyme.