%0 Journal Article
%T Double-duty isomerases: a case study of isomerization-coupled enzymatic catalysis.
%A Solano YJ
%A Kiser PD
%J Trends Biochem Sci
%V 49
%N 8
%D 2024 Aug 17
%M 38760195
%F 14.264
%R 10.1016/j.tibs.2024.04.007
%X Enzymes can usually be unambiguously assigned to one of seven classes specifying the basic chemistry of their catalyzed reactions. Less frequently, two or more reaction classes are catalyzed by a single enzyme within one active site. Two examples are an isomerohydrolase and an isomero-oxygenase that catalyze isomerization-coupled reactions crucial for production of vision-supporting 11-cis-retinoids. In these enzymes, isomerization is obligately paired and mechanistically intertwined with a second reaction class. A handful of other enzymes carrying out similarly coupled isomerization reactions have been described, some of which have been subjected to detailed structure-function analyses. Herein we review these rarefied enzymes, focusing on the mechanistic and structural basis of their reaction coupling with the goal of revealing catalytic commonalities.