The demonstration of a lactosephosphate on the other hand, does bring more certain evidence for the view, hitherto held with very slender experimental support, that phosphorylation is of fundamental importance in lactose synthesis. An isolated instance of the occurrence of such an ester in a trichloroacetic acid extract of cow-udder tissue has already been reported (Malpress, 1950), and it seems probable that this compound may prove to be the immediate precursor of lactose in the mammay gland. SUMMARY 1. Barium fractionation procedures, supplemented by chromatographic analysis, have shown that ax-galactose-1-phosphate, c( ?)-glucose-1-phosphate, glucose-6(?)-phosphate, a lactosephosphate and phosphopyruvic acid are present in trace amounts in normal milk.2. The pomsible significance of these findings in relation to lactose synthesis is discu#sed.Our thanks are due to Mr J. G. Murray (Department of Agricultural Bacteriology) for assistance in obtaining milk samples, and for bacteriological examinations; and to Prof. D. C. Harrison for many valuable discussions.

No abstract

No abstract

No abstract

No abstract