The NADP-dependent trifunctional methylenetetrahydrofolate dehydrogenase purified from mouse liver is immmunologically distinct from the mouse NADP-dependent bifunctional enzyme

Abstract

Methylenetetrahydrofolate dehydrogenase – methenyltetrahydrofolate cyclohydrolase – formyltetrahydrofolate synthetase was purified to homogeneity from mouse liver, taking advantage of its very high affinity for 2′,5′-ADP-Sepharose. Antibodies raised to this trifunctional enzyme and to the bifunctional NAD-dependent dehydrogenase–cyclohydrolase from mouse Ehrlich ascites tumour cells were found not to cross-react with the purified proteins on Western blots. Each of these polyclonal antibodies detects the appropriate protein in extracts of Ehrlich ascites tumour cells after sodium dodecyl sulfate – polyacrylamide gel electrophoresis and electrophoretic transfer of the proteins to nitrocellulose. The procedure has also been used to obtain a purified preparation of the trifunctional enzyme from human liver obtained at autopsy.