Sterling Wheaten

Honors in Chemistry

Major: Chemistry

Supervisor: Michael Messina, Chemistry and Biochemistry

The 2^nd Step in the Michaelis-Menten Mechanism: A Spectroscopic Analogy within a 3-State Quantum Dynamical Picture

In this study we describe the enzyme-catalyzed transfer of an H atom from a reactant to a product following the second step of the Michaelis-Menten Mechanism.  We represent the second step of the Michaelis-Menten Mechanism using a three-state system model, which is comprised of three potential energy surfaces and three wavepackets.  The three potential energy surfaces refer to the initial potential energy of the H atom bond to the reactant in the enzyme-substrate complex, then as time increases, the potential energy of the H atom bond to the product, and finally, the repulsive potential as the product leaves the reactive region.  The three wavepackets, dependent on the H atom coordinate and time, describe the coupling between the potential energy surfaces as the H atom transfers from the reactant surface to the product surface.  This three-state system will enable us to achieve the major goal of this work; to completely describe the time evolved quantum dynamics of the H atom transfer by applying the time-dependent Schrodinger Equation.  We will study how coupling between the surfaces affects the rate constant for enzyme-catalyzed H atom transfers.  Also, we will make an analogy between the Franck-Condon Principle in electronic spectroscopy and the enzyme-catalyzed H atom transfer.