SUMMARY: The strain of Saccharomyces carlsbergensis 4228 studied differed from those previously used for the assay of vitamin B6 in that it required this vitamin for rapid growth in the absence of added thiamine. The rate, rather than the ultimate extent, of growth of the organism is proportional to the concentration of vitamin B6, and the size of the inoculum and its physiological age, the duration and temperature of incubation and the degree of aeration, must be strictly controlled. Non-phos-phorylated forms of the vitamin only are utilized, and natural materials are acid-extracted before assay. The organism responds a little less well to pyridoxamine than it does to pyridoxal and pyridoxine. A linear response curve is obtained over a range of pyridoxine concentrations (0·2 to 2 × 10−8m) when incubation is in static culture at 37° (24 hr.) in a basal medium slightly modified from those previously used.
FournierS. A.,
ThomasM. H.,
SeigelG. L.1951; Vitamin B6
. In Methods of Vitamin Assay, 2nd ed.. p. 217 Ed. The Association of Vitamin Chemists Inc. New York: Interscience Publishers, Inc.;
MonodJ.,
Cohen-BazireG.,
CohnM.1951; Sur la biosynthese de la β-galactosidase (lactase) chez Escherichia coli. La spécificité de l’induction. Biochim. biophys. Acta 7:585
RubinS. H.,
ScheinerJ.,
HirschbergE.1947; The availability of vitamin B6 in yeast and liver for growth of Saccharomyces carlsbergensis
. J. biol. Chem 167:599
SnellE. E.,
RannefeldA. N.1945; The vitamin B6 group. III. The vitamin activity of pyridoxal and pyridoxamine for various organisms. J. biol. Chem 157:475