Studies on the response ofLactobacillus caseito different folate monoglutamates

Abstract

1. The response ofLactobacillus caseiwas measured for a number of the monoglutamyl forms of folate derivatives.2. At the concentrations of folate commonly used in the assay of folate vitamin in foods the response ofL. caseito folic acid, (pteroyl glutamic acid) and 5-formyl-tetrahydrofolic acid was similar, but 5-methyl-tetrahydrofolic acid gave as little as half the response of folic acid.3. The response was modified by altering pH but not by concentration of ascorbate.4. These results have implications for the assays of foods for folate where mixtures of folate derivatives are present.5. A modified procedure is suggested in which the monoglutamates give similar responses.