concentrations. To obtain access to n-6(S)-HPODs, SBLOX-1 is the enzyme of
choice; this is due not only to the fact that this enzyme is by far the best studied
LOX, but also is available commercially and has high specificity. To generate other
PUFA-HPODs, the choice of the catalyst will be dictated mainly by its availability as
well as by its optimum pH (which should be as high as possible), in order to facilitate
substrate dissolution at high concentration. Gene cloning and heterologous expres-
sion may, in the future, represent a means of circumventing the low availability of
LOXs from sources other than vegetal ones – something which remains a bottleneck
to the wider use of such enzymes.
In addition to their use in physiological studies, PUFA-HPODs might also be
employed in very various ways in organic syntheses, as exemplified in Section
2.4. Thus, the combination of chemical and enzymatic methods allows access to
natural products of the linoleic and arachidonic acids cascades in a much easier
manner than does total chemical synthesis. The products derived therefrom could
also be used in the biotechnological production of flavors. Indeed, small molecules
such as hexanal and hexenal (green note), nonenal and nonadienal (cucumber-like
note), octen-1,3-ol (fungal note) are naturally generated by the catabolism of PUFA-
HPODs via an enzyme called hydroperoxide-lyase (Grosch and Wurzenberger, 1984;
Hatanaka, 1993). Thus, combination of these two enzymes might offer a means of
producing such aromas with a natural label. It has also been shown that coriolic acid
might be degraded by yeasts (Albrecht et al., 1992), through theb-oxidation path-
way, to aromatic lactones such asd-decalactone (peach aroma). These selected ex-
amples support the opinion that the field of LOXs is of major interest from both
fundamental and industrial points of view.
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