TY - JOUR
T1 - ATP effects on insulin-degrading enzyme are mediated primarily through its triphosphate moiety
AU - Song, Eun Suk
AU - Juliano, Maria Aparecida
AU - Juliano, Luiz
AU - Fried, Michael G.
AU - Wagner, Steven L.
AU - Hersh, Louis B.
PY - 2004/12/24
Y1 - 2004/12/24
N2 - 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.
AB - 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.
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U2 - 10.1074/jbc.M411177200
DO - 10.1074/jbc.M411177200
M3 - Article
C2 - 15494400
AN - SCOPUS:11144234853
VL - 279
SP - 54216
EP - 54220
IS - 52
ER -