A study, by means of paper chromatography of the growth stimulating properties of liver extract, yeast solubles, and trypsin digest of casein for Lactobacillus casei

Transverse sections of linear partition chromatograms on filter paper when eluted with basal medium for Lactobacillus casei showed Wilson Liver Fraction L to contain at least two growth stimulating factors for this organism. Three growth stimulating factors were demonstrable by this technique in trypsin digest of casein in contrast to dried yeast solubles which contained but one such factor. The growth stimulating factor from yeast was separated and partially purified. Treatment with strong acid suggested the peptide nature of this material. Chromatographic evidence of the presence of glycine, leucine, aspartic acid, and glutamic acid was obtained from the acid hydrolyzate of the yeast factor.