Purification, properties and inhibition of rat liver cytosolic vitamin B12-dependent methionine synthase.

Abstract

The in vitro inactivation of methionine synthase (isolated from E. Coli and pig liver) by N,O has already been demonstrated (1). Here we report: (a) The purification to electrophoretic homogeneity of B12-methionine synthase from rat liver to cytosol using Q-sepharose anion exchange chromatography and Sephacryl S-200 gel filtration.to give a protein of mass 180 kda. (Fig. 1 and 2). The purity was monitored by capillary electrophoresis and SDS-PAGE A second form of B12-MS was eluted from the QSepharose column but was not studied. @) The inhibition of the cytosolic and parhally purified enzyme by N,O and NO. (Fig. 3 and 4).