ATP effects on insulin-degrading enzyme are mediated primarily through its triphosphate moiety

Eun Suk Song, Maria Aparecida Juliano, Luiz Juliano, Michael G. Fried, Steven L. Wagner, Louis B. Hersh

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

It has been reported previously that ATP inhibits the insulysin reaction (Camberos, M. C., Perez, A. A., Udrisar, D. P., Wanderley, M. I., and Cresto, J. C. (2001) Exp. Biol. Med. 226, 334-341). We report here that with 2-aminobenzoyl-GGFLRKHGQ-ethylenediamine-2,4-dinitrophenyl as substrate, ATP and other nucleotides increase the rate > 20-fold in Tris buffer. There is no specificity with respect to the nucleotide; however, ATP is more effective than ADP, which is more effective than AMDP. Triphospkate itself was as effective as ATP, indicating it is this moiety that is responsible for activation. The binding of triphosphate was shown to be at a site distinct from the active site, thus acting as a noncompetitive activator. With the physiological substrates insulin and amyloid β peptide, nucleotides and triphosphate were without effect. However, with small physiological peptides such as bradykinin and dynorphin B-9, ATP and triphosphate increased the rate of hydrolysis -10-fold. Triphosphate and ATP shifted the oligomeric state of the enzyme from primarily dimertetramers to a monomer. These data suggest the presence of an allosteric regulatory site on insulysin that may shift its specificity toward small peptide substrates.

Original languageEnglish
Pages (from-to)54216-54220
Number of pages5
JournalJournal of Biological Chemistry
Volume279
Issue number52
DOIs
StatePublished - Dec 24 2004

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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