Deuterium incorporations from [²H₁]-(1R,2R) and [²H₁]-(1S,2R) glycerols into the fluorine containing antibiotic nucleocidin, in Streptomyces calvus indicate that one deuterium atom is incorporated at the C-5′ site of nucleocidin from each of these isotopomers of glycerol. Two deuteriums become incorporated at C-5′ of nucleocidin after a feeding experiment with [²H₅]-glycerol. These observations indicate that there is no obligate oxidation of the pro-R hydroxymethyl group of glycerol as it progresses through the pentose phosphate pathway and becomes incorporated into the fluorinated antibiotic.