Insulin-degrading enzyme hydrolyzes ATP
María Del Carmen Camberos1, Juan C Cresto
1Centro de Investigaciones Endocrinológicas (CEDIE), Hospital de Niños "Ricardo Gutierrez," Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Buenos Aires, Argentina.
Experimental Biology and Medicine (Maywood, N.J.)
|January 30, 2007
Summary
Insulin-degrading enzyme (IDE) possesses ATPase activity, hydrolyzing ATP to facilitate insulin binding and degradation. This activity is concentration-dependent but unaffected by insulin itself.
Area of Science:
- Biochemistry
- Enzymology
- Molecular Biology
Background:
- Insulin-degrading enzyme (IDE) previously shown to be inhibited by ATP.
- Investigating ATP hydrolysis as a mechanism for reversing IDE inhibition.
Purpose of the Study:
- To determine if IDE possesses ATPase activity.
- To understand the relationship between ATP hydrolysis, insulin degradation, and IDE function.
Main Methods:
- Assessing ATP hydrolysis via (32)P release from gamma[(32)P]ATP.
- Utilizing Sephadex G200 chromatography, immunoprecipitation, and nondissociating gel electrophoresis.
- Kinetic analysis (Michaelis-Menten) and inhibitor studies (orthovanadate).
Main Results:
- IDE exhibits ATP hydrolysis, correlating with insulin degradation.
- ATP hydrolysis follows Michaelis-Menten kinetics (Vmax: 570.45 ± 113.08 pmol Pi/hr, Km: 63.13 ± 3.48 μM).
- IDE has one active hydrolytic ATP binding site; insulin binding induces conformational changes, but insulin does not alter IDE's ATPase activity.
Conclusions:
- IDE possesses intrinsic ATPase activity.
- Insulin binding and degradation are dependent on ATP concentration.
- IDE's ATPase function is distinct from its insulin-degrading role, though linked.
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