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. 2011 May 18;94(1):337S–342S. doi: 10.3945/ajcn.111.013367

TABLE 1.

Relative response of microorganisms to unhydrolyzed folate derivatives1

Lactobacillus casei Streptococcus faecium Pediococcus cerevisiae
Folic acid (PteGlu) 96 100 0
10-Formyl-PteGlu 100 100 0
Dihydrofolate 100 100 0
THF 100 100 100
10-Formyl-THF 99 100 100
5-Formyl-THF 100 100 100
5-Methyl-THF 100 0 0
PteGlu2 100 100 0
PteGlu3 100 0 0
PteGlu4 66 — —
PteGlu5 20 — —
PteGlu6 4 — —
PteGlu7 2 — —
10-Formyl-H4PteGlu3 82 — —
10-Formyl-H4PteGlu5 3 — —
5-Methyl-H4PteGlu3 90 0 0
5-Methyl-H4PteGlu5 2 0 0
5-Methyl-H4PteGlu7 1 — —
Pteroate 0 100 0
10-Formyl-pteroate 0 100 0
5-Formyl-H4 pteroate 0 + 0
1

In most cases, the relative response is a comparison of folate concentration required to support half maximum growth rates of the bacterium. The data were adapted from reference 9. All reduced folates refer to the natural isomer at the C-6 position. 6R,S-5-Methyl-THF and 6R,S-5-formyl-THF, which researchers sometimes use as standards, exhibit half the activity of the 6S-derivatives that correspond to them. THF, tetrahydrofolate; +, some growth but not quantitated.