NTU Undergraduates' research April 2014 - Biosciences | Page 96

THE EFFECTS OF MUTATIONS IN THE HINGE PROTIEN AND
VISCOSITY ON THE RATE OF ELECTRON TRANSFER OF THE
CYTOCHROME P450 REDUCTASE ENZYME
By Simon Ashall

Abstract
The cytochrome P450 reductase enzyme is found in mammalian cells on the endoplasmic
reticulum where it is reduced by NADPH and then by the use of conformational change it
passes the electron through its flavin coenzymes onto an electron acceptor. This
conformational change is seen to be controlled by a 15 amino acid hinge protein. Studies
have shown that by creating a mutant CPR hinge protein that this can have a massive effect
on the rate of electron transfer by the enzyme. In this study by the use of two mutants, 5
alanine and 10 proline, the effect that a change in the hinge protein has on the rate of
electron transfer was examined and showed that the hinge protein is important in
controlling the conformational change of the enzyme as any changes in this protein changed
the rate of electron transfer. After this the effect that viscosity had on the enzyme was
looked at, this helped to prove that a conformational change does occur for the electron
transfer as an increase in viscosity decreased the rate of this electron transfer.