The low reactivity of 5H-dibenzo[a, d]cycloheptene 10,11-oxide in microsomal epoxide hydrolase catalysed hydration.
1. The rate of hydration of 5H-dibenzo[a, d]cycloheptene 10,11-oxide catalysed by rabbit liver microsomal epoxide hydrolase has been compared with that of the acyclic analogue cis-stilbene oxide. The latter was shown to be a much better substrate for the enzyme than the former epoxide. 2. The kinetic parameters for the hydration of 5H-dibenzo[a,d]cycloheptene 10,11-oxide and cis-stilbene oxide have been determined using a rabbit liver microsomal preparation at 37 degrees C and pH 7.4. The much slower hydration of the former is due to a much lower Vs and not to a higher Km relative to the latter epoxide. 3. 5H-Dibenzo[a,d]cycloheptene 10,11-oxide inhibited the hydration of cis-stilbene oxide by rabbit liver microsomal epoxide hydrolase.
Bellucci
G
G
Istituto di Chimica Organica, Facoltá di Farmacia, Universitá di Pisa, Italy.
Chiappe
C
C
Marioni
F
F
Simonelli
C
C
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D003986:Dibenzocycloheptenes / Q000378:metabolism* / Q000494:pharmacology; D004851:Epoxide Hydrolases / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D015394:Molecular Structure; D011817:Rabbits; D013379:Substrate Specificity
D003986:Dibenzocycloheptenes; C060079:5H-dibenzo(a,d)cycloheptene-10,11-oxide; D004851:Epoxide Hydrolases