0000000000052993
AUTHOR
Alan J. Sparrow
Endogenous role of epoxide-hydratase. Development of a steroid epoxide-hydratase assay and properties of the enzyme.
A highly sensitive and rapid radiometric assay for the determination of specific epoxide hydratase activity with a steroid epoxide (16α, 17α-epoxy-1,3,5(10)-estratrien-3-ol, ‘estroxide’) has been developed. The unreacted substrate was separated from the product 1,3,5(10)-estratrien-3,16β,17α-triol by extraction into light petroleum. The product was then extracted into ethyl acetate and measured by scintillation spectrometry. Radiochromatography established that after subtraction of the blank the entire radioactivity measured in the ethyl acetate phase resulted from the product 1,3,5(10)-estratrien-3,16,17-triol, whilst high performance liquid chromatography with the four possible isomers of…
Radioactively labelled epoxides. Part IV. Tritium labelled α- and β-methyl styrene oxides
Tritium labelled α-methyl styrene oxide (2-methyl-2-phenyloxirane) and cis- and trans-β-methyl styrene oxides (Z- and E-2-methyl-3-phenyl oxirane) have been prepared using tritiated water as the inexpensive source of tritium. The two geometrical isomers of β-methyl styrene oxide were synthesized by a sequence of reactions which led to stereochemically pure products, and obviated any need to separate the isomers.
Radioactively labelled epoxides. Part III. Tritium labelled steroid 16α, 17α-epoxides
Tritium labelled (17-3H) 16α, 17α-epoxy-androst-4-en-3-one and 16α, 17α-epoxy-estra-1,3,5(10)-trien-3-ol have been prepared on a large scale (200-300 mg amounts) with efficient (i.e. activity of product exactly predictable) introduction of label. The preparative method is very inexpensive, since the tritium derives from tritiated water, the steroid starting materials are readily available, and high yields are obtained in all steps.
Radioactively labelled epoxides part II. (1) tritium labelled cyclohexene oxide, transstilbene oxide and phenanthrene 9,10-oxide
Tritium labelled cyclohexene oxide, trans-stilbene oxide and phenanthrene 9,10-oxide were prepared with specific activities of 0.7 - 1.1 mCi per mmole starting with monoor diketo compounds. Tritium was introduced by reducing the ketone precursors with tritiated complex metal hydrides. The resulting alcohols were transformed to the epoxides by methods described for the unlabelled compounds. The syntheses require only two or three steps and yield cyclohexene oxide, trans-stilbene oxide and phenanthrene 9,10-oxide, important substrates for the study of epoxide hydratase and glutathione S-transferases in high radiochemical purity.