Article

Antonie van Leeuwenhoek

, Volume 21, Issue 1, pp 385-396

Chemical and biological studies on 1,2-dihydro-s-triazines

VII. Activity in pteroylglutamic acid-Lactobacillus casei # 7469 systems
  • G. E. FoleyAffiliated withLabratoires of Microbiology, The Children's Cancer Research FoundationDepartment of Pathology, Harvard Medical School, at The Children's Medical Center
  • , E. C. HaleyAffiliated withLabratoires of Microbiology, The Children's Cancer Research FoundationDepartment of Pathology, Harvard Medical School, at The Children's Medical Center

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Summary

A series of 1,2-dihydro-s-triazines has been studied inLactobacillus casei # 7469-pteroylglutamic acid systems. The active derivatives exhibit a competitive inhibition similar to that of 4-aminopteroylglutamic acid, but differ from the latter in that inhibition is not relieved by adenine or guanine, and at appropriate concentrations of inhibitor, is not reversed by excess pteroylglutamic acid. Differences in microbiological activity can be correlated with certain alterations in the structure of the molecule, maximum activity being exhibited by the 2,2-dimethyl-phenyl- and 2,2-dimethyl-m-chlorophenyl derivatives.

The inhibitory effect of these compounds is reversed·by appropriate concentrations of dihydropteroylglutamic acid, N10-formylpteroylglutamic acid, synthetic and natural citrovorum factor, thymine and thymidine. The similarity in inhibition indices obtained vs the various forms of pteroylglutamic acid inLactobacillus casei bioassay systems and the correlation with those vs citrovorum factor inStreptococcus faecalis # 8043 andLeuconostoc citrovorum # 8081 bioassay systems suggests that inhibition ofLactobacillus casei is the result of interference with the utilization of citrovorum factor.