title: Asymmetric sulfoxidations mediated by alpha-chymotrypsin.
abstract: The oxidation of aryl alkyl sulfides with H(2)O(2) in aqueous solution is a reasonably facile reaction producing racemic sulfoxides. We show that in the presence of the hydrolytic enzyme alpha-chymotrypsin such a sulfoxidation is accelerated and, more importantly, becomes stereoselective. With phenyl isobutyl sulfide as a model, the chymotrypsin-mediated, highly asymmetric oxidation is shown to occur in the hydrophobic binding pocket of the enzyme active site. The stereoselectivity of the chymotrypsin-mediated sulfoxidations is correctly explained by means of structure-based molecular modeling of the enzyme-sulfide complexes.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
authors.forename: Prasanta Kumar
authors.initials: PK
authors.lastname: Das
authors.forename: Jose M M
authors.initials: JM
authors.lastname: Caaveiro
authors.forename: Susana
authors.initials: S
authors.lastname: Luque
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Klibanov
mesh_terms: D000818:Animals; D002417:Cattle; D002918:Chymotrypsin / Q000378:metabolism*; D003198:Computer Simulation; D006861:Hydrogen Peroxide / Q000737:chemistry; D008958:Models, Molecular; D008968:Molecular Conformation; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013237:Stereoisomerism; D013454:Sulfoxides / Q000138:chemical synthesis*
chemical_list: D013454:Sulfoxides; D012710:Serum Albumin, Bovine; D006861:Hydrogen Peroxide; D002918:Chymotrypsin; C117608:alpha-chymotrypsin