Enzyme kinetics (Michaelis-Menten)

Published on April 19, 2020 Reviewed on November 27, 2022   41 min

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Hello. Welcome to this Principles of Biochemistry lecture series. I'm Jerry Feigenson, a professor in the Department of Molecular Biology and Genetics at Cornell University in the USA. In the eighth lecture, you learned about different types of enzymes and some principles of enzyme kinetics. And you saw that enzyme catalysts work by two different principles, binding to and stabilizing the transition state and forcing the mechanism to follow a pathway that has a lower transition state free energy.
In this ninth lecture, you will learn how useful is the concept of initial reaction velocity. And you will see that plotting initial reaction velocity versus substrate concentration shows a big difference between catalyzed and uncatalyzed reactions. You will see the usefulness of what is called Michaelis-Menten kinetics. We'll see pre-energy barriers at every step along the reaction pathway. And we will see the usefulness of the double-reciprocal or Lineweaver-Burk plot to find kinetic parameters.
Just to remind you, before we start talking more about catalysis, let me summarize how catalysts work. Only two ways: first, whatever is the transition state, the enzyme will bind to it and stabilize it, thereby lowering its free energy. Or whatever is the uncatalyzed reaction mechanism, the enzyme will change it. The enzyme will force a new reaction path that has a lower free energy transition state.