J. Biol. Chem., Vol. 262, Issue 16, 7463-7471, 06, 1987
The regiochemistry and stereochemistry of the biosynthesis of vitamin B6 from triose units
RE Hill, A Iwanow, BG Sayer, W Wysocka and ID Spenser
13C and 2H NMR spectroscopy has been employed to probe the biosynthesis of
vitamin B6 in Escherichia coli. The 13C NMR spectrum of a sample of
pyridoxol derived biosynthetically from D-[1,2,3,4,5,6-13C6]glucose shows
that the bonds, C(2)-C(3) and C(4)-C(5), of the pyridine nucleus are the
only two carbon-carbon bonds of pyridoxol which are generated de novo in
the course of its biosynthesis from glucose. It follows that the pyridoxol
skeleton is generated from two intact triose units and a triose-derived
two-carbon unit, all of which are supplied by glucose. From the 2H NMR
spectra of samples of pyridoxol derived from (R)-[1,1- 2H2]glycerol and
(S)-[1,1-2H2]glycerol, respectively, it can be deduced that the
rehydroxymethyl group of glycerol enters C-2', C-4', and C-5' of the
pyridoxol skeleton. It follows that each of the three fragments is derived
from glycerol in stereo-specific fashion. These results answer questions
concerning the regiochemistry and the stereochemistry of pyridoxol
biosynthesis.