1. Cell-free extracts of Penicillium charlesii G. Smith were used in a study of the biosynthesis of the galactofuranose polymer, galactocarolose. 2. UDP-glucose and UDP-galactopyranose were precursors of galactocarolose and it was shown that the galactofuranose residues in the polymer were formed from glucose without fission of the hexose carbon chain. 3. A new nucleotide, UDP-α- d -galactofuranose, was formed by the system and was a major product when polymer synthesis was inhibited by F - or Zn 2+ ; the nucleotide was isolated and its structure determined. 4. UDP-α- d -galactofuranose was efficiently utilized for polymer synthesis and shown to be formed from the pyranose nucleotides. 5. A route for the biosynthesis of galactocarolose, involving a novel ring contraction of the hexose residue while still attached to the nucleotide, is proposed.
1. The phosphate groups in the type-specific substance S.34 from Pneumococcus type 34 (U.S. type 41) were shown to join the hydroxyl group at position 1 or 5 of ribitol and the hydroxyl group at position 3 of a d -galactofuranosyl residue in the next repeating unit. 2. A partial structure of the type-specific substance was derived. 3. New syntheses of d -galactose 2-phosphate and d -galactose 3-phosphate are described.