Enzyme kinetics from circular dichroism of insulin reveals mechanistic insights into the regulation of insulin-degrading enzyme.

Content Provider	Europe PMC
Author	Ivancic, Valerie A. Krasinski, Claire A. Zheng, Qiuchen Meservier, Rebecca J. Spratt, Donald E. Lazo, Noel D.
Copyright Year	2018
Abstract	Insulin-degrading enzyme (IDE) is a zinc metalloprotease that selectively degrades biologically important substrates associated with type 2 diabetes and Alzheimer’s disease (AD). As such, IDE is an attractive target for therapeutic innovations. A major requirement is an understanding of how other molecules present in cells regulate the activity of the enzyme toward insulin, IDE’s most important physiologically relevant substrate. Previous kinetic studies of the IDE-dependent degradation of insulin in the presence of potential regulators have used iodinated insulin, a chemical modification that has been shown to alter the biological and biochemical properties of insulin. Here, we present a novel kinetic assay that takes advantage of the loss of helical circular dichroic signals of insulin with IDE-dependent degradation. As proof of concept, the resulting Michaelis–Menten kinetic constants accurately predict the known regulation of IDE by adenosine triphosphate (ATP). Intriguingly, we found that when Mg2+ is present with ATP, the regulation is abolished. The implication of this result for the development of preventative and therapeutic strategies for AD is discussed. We anticipate that the new assay presented here will lead to the identification of other small molecules that regulate the activity of IDE toward insulin.
Page Count	10
ISSN	01448463
Volume Number	38
PubMed Central reference number	PMC6239264
Issue Number	6
PubMed reference number	30305381
Journal	Bioscience Reports [Biosci. Rep]
e-ISSN	15734935
DOI	10.1042/BSR20181416
Language	English
Publisher	Portland Press Ltd.
Publisher Date	2018-11-07
Access Restriction	Open
Rights License	This is an open access article published by Portland Press Limited on behalf of the Biochemical Society and distributed under the Creative Commons Attribution License 4.0 (CC BY). © 2018 The Author(s).
Subject Keyword	circular dichroism insulin-degrading enzyme insulin Michaelis-Menten kinetics
Content Type	Text
Resource Type	Article
Subject	Cell Biology Molecular Biology Biochemistry Biophysics