title: An indirect role of vitamin B12 in regulation of thymidylate synthase in Lactobacillus leichmannii.
abstract: Vitamin B12 augments thymidylate synthase function in L. leichmannii by facilitating indirectly the availability of suitable nonmethylpolyglutamylfolate cofactors. This is effected by the demethylation of trapped methyltetrahydrofolates, catalysed by a vitamin B12 requiring methionine synthase. Deoxyuridine supplemented cells, lacking in B12, have decreased levels of methionine synthase and thymidylate synthase. Addition of active and inactive conjugase preparation as a source of mono and polyglutamylfolates indicated that the latter are the preferred cofactors for thymidylate synthase.
authors.affiliation: Biochemistry Division, Bhabha Atomic Research Centre, Bombay, India.
authors.forename: C P
authors.initials: CP
authors.lastname: Nair
authors.forename: J M
authors.initials: JM
authors.lastname: Noronha
mesh_terms: D007778:Lactobacillus / Q000201:enzymology*; D013940:Thymidylate Synthase / Q000378:metabolism*; D014805:Vitamin B 12 / Q000502:physiology*
chemical_list: D013940:Thymidylate Synthase; D014805:Vitamin B 12