The identification of ethylene oxide as a major metabolite of ethylene in Vicia faba L

Ethylene oxide has been positively identified as a metabolite of ethylene in developing cotyledons of broad bean by co-chromatography with the authentic compound and by mass spectrometry. In excess of 95% of applied [ 14 C]ethylene (3 μl/l) was metabolized in less than 2 h with 85-95% of the 14 C appearing in ethylene oxide. The metabolism is a property of the tissue and is not due to either micro-organisms or wounding.

2-O-methyl-D-glucuronic acid, a new hexuronic acid of biological origin

Acid hydrolysis of the extracellular polysaccharide of Porphyridium cruentum (a unicellular red alga) produced a mixture of aldobiuronic acids and free hexuronic acids. Fractionation of this mixture on an ion-exchange column yielded a hexuronic acid characterized as the title compound. Its identity was confirmed by chromatographic comparisons with the authentic compound, by reduction to the corresponding methylated aldose, by resistance to controlled lead tetra-acetate oxidation and by chemical-ionization mass spectrometry. Complete spectra have been deposited as Supplementary Publication SUP50062 (7 pages) with the British Library (Lending Division), Boston Spa, Wetherby, W. Yorkshire LS23 7BQ, U.K., from whom copies may be obtained under the terms given in Biochem. J. (1976) 153, 5.

METABOLISM OF 6-CHLORO-9α,10α-PREGNA-1,4,6-TRIENE-3,20-DIONE IN RAT, RABBIT, MONKEY AND MAN

ABSTRACT When 6-chloro-9β,10α-pregna-1,4,6-triene-3,20-dione (trengestone) was incubated with liver slices of male rats, the substrate was rapidly transformed to a polar metabolite; in contrast, liver slices of female rats metabolised trengestone much more slowly, and only traces of a polar metabolite could be detected. After paper and thin layer chromatography in various systems, the polar metabolite was obtained in crystalline form and identified as 6-chloro-16α-hydroxy-9β,10α-pregna-1,4,6-treiene-3,20-dione (16α-hydroxytreengestone) by its infrared spectrum and by gas chromatography-mass spectrometry. After administration of trengestone to male or female rats, the main metabolite in the urine was again a6α-hydroxytrengestone. When trengestone was incubated with liver slices of male or female human subjects, two metabolites were detected, one of which was formed in large amounts. By comparison with the authentic compound, the major metabolite proved to be identical with (20S)-6-chloro-20-hydroxy-9β,10α-pregna-1,4,6-triene-3-one (20α-hydroxytrengestone). After oral administration of radioactive trengestone to man, the amount of total radioactivity in the urine was considerably greater in a human female (50 %) than in two human males (6–8 %). The main metabolite of trengestone was identified as 20α-hydroxytrengestone. When trengestone was given orally to a female rabbit, and to a female Rhesus monkey, both the 20α-hydroxy and the 2β-hydroxy derivatives of trengestone were detected in the urine. These experiments demonstrate considerable differences in the metabolism of the rat, rabbit, monkey, and man.