Related Experiment Video
Updated: Aug 17, 2026

Enzymatic Cascade Reactions for the Synthesis of Chiral Amino Alcohols from L-lysine
Published on: February 16, 2018
Structure and enzymology of Delta5-3-ketosteroid isomerase
1National Creative Research Initiative Center for Biomolecular Recognition, Pohang University of Science and Technology, Pohang, 790-784, Kyungbuk, South Korea.
Abstract:
The three-dimensional structures of Delta5-3-ketosteroid isomerases from two different bacterial species have been determined. The structures reveal an unusually apolar active site, in which each of several competitive inhibitors of the enzyme are held by two hydrogen bonds with the general acids Tyr14 and Asp99, and by hydrophobic interactions. The hydrogen bond between the Tyr14 hydroxyl and the C3 oxyanion of a transition-state analog is a low-barrier hydrogen bond, as indicated by a highly deshielded nuclear magnetic resonance. Structural and other biochemical studies have enabled the proposal of a detailed catalytic mechanism for Delta5-3-ketosteroid isomerase and provided a major thrust towards understanding the mechanism not only in chemical terms but also in energetics terms.
More Related Videos
08:02Benchtop Immobilized Metal Affinity Chromatography, Reconstitution and Assay of a Polyhistidine Tagged Metalloenzyme for the Undergraduate Laboratory
Published on: August 23, 2018
13:05Enzymatic Synthesis of Epoxidized Metabolites of Docosahexaenoic, Eicosapentaenoic, and Arachidonic Acids
Published on: June 28, 2019
Related Concept Videos
Disubstituted Cyclohexanes: cis-trans Isomerism
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
Stereoisomerism of Cyclic Compounds
E2 Reaction: Stereochemistry and Regiochemistry
When a substrate with two different β hydrogens undergoes an E2 elimination, the presence of a strong base can yield two regioisomeric alkenes. The more-substituted alkene is the major product and...
Intramolecular Claisen Condensation of Dicarboxylic Esters: Dieckmann Cyclization
Diels–Alder Reaction Forming Cyclic Products: Stereochemistry
Keto–Enol Tautomerism: Mechanism