ketosteroid isomerase: Many biological reactions proceed by enzymatic cleavage of a C-H bond adjacent to carbonyl or a carboxyl group, leading to an enol or a enolate intermediate that is subsequently re-protonated at the same or an adjacent carbon. Ketosteroid isomerases are important members of this class of enzymes which are the most proficient of all enzymes known and have served as a paradigm for enzymatic enolizations since its discovery in 1954. This CD includes members of this class that calalyze the isomerization of various beta,gamma-unsaturated isomers at nearly a diffusion-controlled rate. These enzymes are widely distributed in bacteria.
Jiyao W et al.(2023). "The conserved domain database in 2023.",