Ketosteroid Isomerase
From Proteopedia
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<applet load='1ISK' size='300' frame='true' align='right' caption='Ketosteroid Isomerase (KSI; PDB 1ISK)' scene='User:Laura_M._Haynes/Sandbox_1/Ksi/4' /> | <applet load='1ISK' size='300' frame='true' align='right' caption='Ketosteroid Isomerase (KSI; PDB 1ISK)' scene='User:Laura_M._Haynes/Sandbox_1/Ksi/4' /> | ||
| - | Ketosteroid isomerase (KSI, EC#5.3.3.1) is an enzyme that catalyzes the isomerization of 3-oxo-Δ<sup>5</sup> ketosteroids to their hormonally active Δ<sup>4</sup>-conjugated isomers. | + | Ketosteroid isomerase (KSI, EC#5.3.3.1) is an enzyme that catalyzes the isomerization of 3-oxo-Δ<sup>5</sup> ketosteroids to their hormonally active Δ<sup>4</sup>-conjugated isomers.<ref>PMID:15381400</ref> |
This reaction is essential in the biosynthesis of steroids in mammals where KSI is a membrane-bound complex. In bacteria, however, KSI exists as a soluble protein is involves in catabolism of steroids. It is one of the most proficient known enzymes with an essentially diffusion limited rate of catalysis. An NMR solution phase structure of KSI | This reaction is essential in the biosynthesis of steroids in mammals where KSI is a membrane-bound complex. In bacteria, however, KSI exists as a soluble protein is involves in catabolism of steroids. It is one of the most proficient known enzymes with an essentially diffusion limited rate of catalysis. An NMR solution phase structure of KSI | ||
Revision as of 18:32, 2 April 2010
Contents |
Introduction
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Ketosteroid isomerase (KSI, EC#5.3.3.1) is an enzyme that catalyzes the isomerization of 3-oxo-Δ5 ketosteroids to their hormonally active Δ4-conjugated isomers.[1]
This reaction is essential in the biosynthesis of steroids in mammals where KSI is a membrane-bound complex. In bacteria, however, KSI exists as a soluble protein is involves in catabolism of steroids. It is one of the most proficient known enzymes with an essentially diffusion limited rate of catalysis. An NMR solution phase structure of KSI
Structure
Ketosteroid isomerase exits as a 28 kDa homodimeric protein.
Enzyme Mechanism
Related Proteins
Available Structures
Proteopedia Page Contributors and Editors (what is this?)
Laura M. Haynes, Michal Harel, Joel L. Sussman, Alexander Berchansky
