NTU Undergraduates' research April 2014 - Biosciences | Page 91

N0387618
Iknam SINGH

ENZYME KINETICS: LIGAND INHIBITION IN ELECTRON TRANSFER ENZYMES
ABSTRACT: Cytochrome P450 reductase is a ~78kDb membrane bound flavoprotein located in the endoplasmic
reticulum. It is responsible for the transfer of electrons that are required by several biological mechanisms. A
cytochrome C assay is conducted in the presence of just NADPH, NADPH and 2,5ADP and 3’AMP at different
concentrations to establish the mechanism of ligand inhibition in electron transfer enzymes. The main findings
showed that 2’5ADP binds to the FAD domain causing inhibition, whereas 3’AMP does not have any catalytic
effect. The Michaelis-Menten equation and Lineweaver-Burk plot showed that an increase concentration in
2’5ADP causes greater inhibition and conformational change of cytochrome p450 reductase decreasing the
rate in which cytochrome C is reduced