PMC

a Nonenzymatic epoxide ring-opening reactions involving addition of a nucleophile (Nuc) under basic or acidic conditions. b Enzymatic epoxide ring-opening reactions by epoxide hydrolases (EHs) and oxidoreductases (ORs). c Epoxide ring-opening reactions of fluostatin C (1), either enzymatically catalyzed by the hydrolase Alp1U, or nonenzymatically mediated by FAD and NADH as reported in this study.

Epoxide carboxylase component II from Xanthobacter strain Py2 confers epoxide isomerase activity in cell extracts of N. corallina. Assays were performed with cell extracts of propylene-grown N. corallina (7.5 mg) in the absence of CO₂. Closed symbols, epoxypropane remaining; open symbols, acetone produced; inverted triangles, addition of epoxide carboxylase component I (0.8 mg); squares, addition of epoxide carboxylase component II (0.6 mg); circles, addition of epoxide carboxylase component III (0.5 mg); triangles, addition of epoxide carboxylase component IV (0.6 mg).

In vitro characterization of KedF as an epoxide hydrolase using (R)- and (S)-styrene epoxide as substrate mimics, preferring (S)-styrene epoxide with a 4.0-fold greater specificity. (A) Regio- and stereoselectivity of KedF-catalyzed hydrolysis of (R)- and (S)-styrene epoxide and HPLC chromatograms with UV detection at 254 nm showing (R)- and (S)-1-phenyl-1,2-ethanediol, respectively, as the major product: (I) (S)-1-phenyl-1,2-ethanediol standard, (II) KedF with (S)-styrene epoxide, (III) (R)-1-phenyl-1,2-ethanediol standard, (IV) KedF with (R)-styrene epoxide, (V) (R)- and (S)-1-phenyl-1,2-ethanediol standards, (VI) KedF with racemic styrene epoxide; (R)- (◆) and (S)-1-phenyl-1,2-ethanediol (◇). (B) Steady-state kinetic analysis of KedF-catalyzed hydrolysis of (R)- and (S)-styrene epoxide showing single substrate kinetic plots for (I) (R)-styrene epoxide and (II) (S)-styrene epoxide.

Phylogenetic tree of haloalkane dehalogenases and epoxide hydrolases. The sequence designations for haloalkane dehalogenases are shown in Table , and the sequence designations for epoxidases are as follows: Hyes_human, soluble epoxide hydrolase from Homo sapiens; Hyep_human, microsomal epoxide hydrolase from H. sapiens; Hyep_rat, microsomal epoxide hydrolase from rat; Hyes_mouse, soluble epoxide hydrolase from mouse; Hyes_rat, soluble epoxide hydrolase from rat; Hyep_rabit, microsomal epoxide hydrolase from rabbit; and Stu02494, epoxide hydrolase from Solanum tuberosum. The sequences used for fingerprinting of epoxide hydralases were obtained from the Protein Motif Fingerprint Database (). The numbers at the nodes are the confidence values for the groups derived from 1,000 rounds of the bootstrap procedure.