Abstract
A simple method for microbiological assay of pyridoxal was investigated by using Sacch. carlsbergensis. When the growth-stimulating activity of pyridoxal was compared with those of pyridoxal derivatives, the activity of pyridoxal-oxime was found to be negligibly low on assay ; that was only 1/100 the potency of pyridoxal. From the results, it was suggested that the pyridoxal content in vitamin B_6 solution can be calculated by the subtraction of activity of hydroxylamine-treated vitamin B_6 solution from the total activity. The formation of oxime from pyridoxal was carried out by the addition of 1 mg of hydroxylamine to the solution containing each 10μg of pyridoxal, pyridoxol and pyridoxamine, and by boiling for 10 min. at pH 6.5. When the pyridoxal contents in dried yeasts, rat livers and kidneys were determined by this method, the recovery values were 103-114%.
