During the course of a transaminase reaction the enzyme exists in two states; one containing bound pyridoxal phosphate and the other containing bound pyridoxamine phosphate. Kinetically a transaminase reaction
A) can be classified as an ordered sequential reaction.
B) will show sigmoidal kinetics with respect to the amino acid substrate.
C) is an example of an enzyme displaying ping-pong kinetics.
D) will give non-linear Lineweaver-Burk plots when product inhibition is measured.
E) cannot be fit to Michaelis-Menten kinetics due to the existence of two enzyme forms.

Question

Quizplus · Accepted Answer

A transaminase reaction is an example of an enzyme displaying ping-pong kinetics, where the enzyme and substrate undergo a series of reactions and form products in a stepwise fashion. In this case, the enzyme exists in two states, one containing pyridoxal phosphate and the other containing pyridoxamine phosphate. This leads to the ping-pong mechanism, where the amino group of the amino acid substrate is transferred to the keto group of the coenzyme, forming pyridoxamine phosphate, which then transfers the amino group to the ketone acceptor, forming the amino acid product and pyridoxal phosphate.

During the Course of a Transaminase Reaction the Enzyme Exists