(65g) Enhanced Affinity of An Insulin Degrading Enzyme Mutant towards Insulin
AIChE Annual Meeting
Monday, October 17, 2011 - 2:40pm to 3:00pm
Insulin-degrading enzyme (IDE), Zn +2 metalloprotease, is key enzyme in the catabolism of both amyloid beta (Aβ), and insulin. IDE is known to exist as an equilibrium mixture of monomers, dimers and higher oligomers with dimer being in predominant form. Distal sites of IDE also have key roles in the catabolism other than catalytic site and exosite. Therefore, the identification of distal sites which have roles in the activity of IDE is crucial for the development of drugs to regulate the activity of IDE. We generated mutant IDE by random mutagenesis with the aid of Taq polymerase error rate. The mutation T797A increases the affinity of the enzyme for insulin binding with a Km value of 47.5 nM compared to the wild type IDE Km value of 87.1 nM. This mutant IDE has also been observed to have lower catalysis towards the degradation of substrate V by about 20 %.This site represents new regions that may take part in the activity of IDE, and shows the possibility of modulating the proteolytic activity of IDE at sites other than its catalytic site or exosite.