In an anaerobic system soya-bean lipoxygenase together with linoleic acid induces a structural rearrangement of 13-hydroperoxyoctadeca-cis-9-trans-11-dienoic acid leading to the formation of 13-oxotrideca-cis(trans)-9-trans-11-dienoic acid and n-pentane as well as 13-oxo-octadeca-9,11-dienoic acid. It is proposed that the 13-peroxyoctadeca-cis-9-trans-11-dienoic acid radical formed through hydrogen radical abstraction by the linoleic acid radical is the key intermediate for these reactions.

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Prions-infectious agents involved in transmissible spongiform encephalopathies-normally survive proteolytic and mild protein-destructive processes. Using bacterial keratinase produced by Bacillus licheniformis strain PWD-1, we tested conditions to accomplish the full degradation of prion protein (PrP) in brain-stem tissue from animals with bovine spongiform encephalopathy and scrapie. The detection of PrPSc, the disease-associated isoform of PrP, in homogenates was done by Western blotting and various antibodies. The results indicated that only in the presence of detergents did heat pretreatment at >100 degrees C allow the extensive enzymatic breakdown of PrPSc to a state where it is immunochemically undetectable. Proteinase K and 2 other subtilisin proteases, but not trypsin and pepsin, were also effective. This enzymatic process could lead to the development of a method for the decontamination of medical and laboratory equipment. The ultimate effectiveness of this method of prion inactivation has to be tested in mouse bioassays.

The interaction of soybean lipoxygenase-1 with 13-~-hydroperoxy-94~, 11 -trans-octadecadienoic acid (1 3-hydroperoxy-linoleate), the product of the enzymic dioxygenation of linoleic acid, yields either a yellow or a purple-coloured enzyme species depending on the amount of product used. With an excess of 13-hydroperoxy-linoleate a labile purple-coloured enzyme species is formed which reverts to a yellow-coloured form with concomitant conversion of the hydroperoxy compound. In this reaction 13-hydroperoxy-linoleate isomerises into threo-11-hydroxy-trans-12 : 13 epoxy-94s-octadecenoic acid as could be concluded from nuclear magnetic resonance and mass spectral data.Experiments with 1 3-[1s02]hydroperoxy-linoleate showed a high retention (70 %) of the two hydroperoxy oxygen atoms in the end product.

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