Unexpectedly enhanced stereoselectivity of peroxidase-catalyzed sulfoxidation in branched alcohols.
Lyophilized horseradish peroxidase (HRP) exhibits poor stereoselectivity in the sulfoxidation of thioanisole when the enzyme is either redissolved in water or suspended in organic solvents. However, when HRP is co-lyophilized in the presence of lyoprotectants or ligands, its stereoselectivity, although still low in most organic solvents, increases up to 4-fold if assayed in secondary or tertiary alcohols (but not in their linear isomers). A mechanistic hypothesis is presented explaining this puzzling phenomenon on the basis of a model of the active site of the enzyme-substrate complex derived from its X-ray crystal structure by means of molecular dynamics and energy minimization.
Xie
Yuchun
Y
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Das
Prasanta Kumar
PK
Caaveiro
Jose M M
JM
Klibanov
Alexander M
AM
D000438:Alcohols / Q000737:chemistry*; D002384:Catalysis; D003198:Computer Simulation; D006735:Horseradish Peroxidase / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013454:Sulfoxides / Q000737:chemistry*
D000438:Alcohols; D013454:Sulfoxides; D006735:Horseradish Peroxidase