[Tetrazolium bioautography of pteroylglutamic acid conjugates].

A microbioautographic method for the identification of pteroylglutamic acid derivatives and their glutamyl conjugates is described. Chromatograms or pherograms of mixtures of the compounds are treated with chicken pancreas conjugase, followed by tetrazolium bioautography. This combined procedure allows qualitative and semi-quantitative analyses of folate compounds in biological material in the nano- and picomole range. Application of this method to extracts of different sources proved the following: (1) the presence of 10-formyl pteroyl-γ-heptaglutamate as the only folate derivative in yeast boiled juice; (2) Clostridium kluyverii and pastorianum contain almost exclulively pteroyl-γ-triglutamic acid; (3) the main folate activity in human leucocytes is 5-methyltetrahydropteroyl monoglutamate.