1. The biosynthesis of the wall teichoic acid in Staphylococcus lactis I3 was studied. Cell-free particulate enzyme preparations, probably representing fragmented membrane, were isolated and used for the synthesis of polymer. 2. By using appropriately labelled CDP-glycerol and UDP-N-acetylglucosamine it was shown that the former contributes a glycerol phosphate residue and the latter contributes an N-acetylglucosamine 1-phosphate residue to the repeating unit. 3. No polymer was synthesized unless both nucleotides were present, and no other substrates were required. 4. The properties of the enzyme system were studied. 5. Although attempts to fractionate the system failed, the biosynthesis is believed to be complex and its mechanism is considered.
