Synthesis of fluoroacetate from fluoride, glycerol, and β- hydroxypyruvate by Streptomyces cattleya

Streptomyces cattleya produces fluoroacetate and 4-fluorothreonine from inorganic fluoride added to the culture broth. We have shown by ¹⁹F nuclear magnetic resonance (NMR) spectrometry that fluoroacetate is accumulated first in the culture broth and that accumulation of 4-fluorothreonine is next. To show precursors of the carbon skeleton of fluoroacetate, we carried out tracer experiments with various ¹⁴C- and ¹³C-labeled compounds. Radioactivity of [U-¹⁴C]glucose, [U-¹⁴C]glycerol, [U-¹⁴C]serine, and [U-¹⁴C]β-hydroxypyruvate was incorporated into fluoroacetate to an extent of 0.2 to 0.4%, whereas [3-¹⁴C]pyruvate, [2,3-¹⁴C]succinate, and [U- ¹⁴C]aspartate were less efficiently incorporated (0.04 to 0.08%). The addition of [2-¹³C]glycerol to the mycelium suspension of Streptomyces cattleya caused exclusive enrichment of the carboxyl carbon of fluoroacetate with ¹³C; about 40% of carboxyl carbon of fluoroacetate was labeled with ¹³C. We studied the radioactivity incorporation of [3-¹⁴C]-, [U-¹⁴C]-, and [1-¹⁴C]β-hydroxypyruvates to show that C-2 and C-3 of β-hydroxy pyruvate are exclusively converted to the carbon skeleton of fluoroacetate. These results suggest that the carbon skeleton of fluoroacetate derives from C-1 and C-2 of glycerol through β-hydroxypyruvate, whose hydroxyl group is eventually replaced by fluoride.