Περίληψη:
The reactivity of 6-phosphogluconolactone and of delta-gluconolactone
with hydroxylamine (a model compound in electrophilicity determination
studies) was examined and compared with the reactivity of several other
electrophiles, such as acid anhydrides and esters, some of which exhibit
adverse biological effects (e.g. carcinogenicity). At pH 7.6 and 30
degrees C, and with an excess of hydroxylamine concentration, most of
the compounds tested disappear from the medium in a monoexponential
reaction. On the other hand, the reaction of 6-phosphogluconolactone
with hydroxylamine is biexponential. This finding indicates the
existence of 6-phosphogluconolactone in two interconvertible, isomeric
forms. The reactivity, towards hydroxylamine, of 6-phosphogluconolactone
and, to a lesser extent of delta-gluconolactone, is on the upper scale
of reactivity of the electrophiles tested. It is concluded that
6-phosphogluconolactone (and in particular, one of its isomeric forms)
is a highly electrophilic compound, and may possibly react with sundry
intracellular nucleophiles, thereby exerting untoward metabolic effects.
In this connection, it is of interest that a positive correlation has
been found to exist between glucose-6-phosphate dehydrogenase activity
and cell proliferation. (Dessi et al., Oncology 45 (1988) 287-291). (C)
1998 Elsevier Science Ireland Ltd. All rights reserved.
