In this episode, we explore enzyme kinetics and inhibition, key concepts for the MCAT Bio/Biochem section. We’ll cover how enzymes accelerate biological reactions by lowering activation energy and introduce two models for enzyme-substrate interaction: the lock-and-key model and the induced fit model.

You'll learn how to apply the Michaelis-Menten equation, focusing on factors like Km and Vmax to understand enzyme efficiency and substrate binding. We’ll also break down the different types of enzyme inhibition—competitive, non-competitive, and uncompetitive—and their effects on enzyme activity. Finally, we discuss the six major types of enzymes and their roles in biological processes, with examples like ligases, isomerases, and hydrolases.

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(00:00) Introduction to enzyme kinetics and inhibition

(01:58) Definition of enzymes and their role

(03:50) Enzyme models: lock and key vs. induced fit

(06:28) Michaelis-Menten Equation

(10:53) Association and dissociation constants

(12:34) Kcat and catalytic efficiency

(14:43) Assumptions of Michaelis-Menten

(18:23) Lineweaver-Burk Plot: linearized Michaelis-Menten Equation

(21:09) Enzyme inhibition: reversible vs. irreversible

(22:14) Competitive inhibition: Km and Vmax

(24:46) Non-competitive inhibition: Effects on Km and Vmax

(27:20) Irreversible inhibition

(29:13) Allosteric inhibition

(31:26) Homotropic and feedback inhibition

(37:40) Common biological enzymes: dehydrogenase, synthetase, and kinase

(43:44) MCAT Advice of the Day