Information on EC 2.5.1.151 - alkylcobalamin dealkylase

This mammalian enzyme, which is cytosolic, can bind internalized methylcob(III)alamin and adenosylcob(III)alamin and process them to cob(I)alamin using the thiolate of glutathione for nucleophilic displacement. The product remains bound to the protein, and, following its oxidation to cob(II)alamin, is transferred by the enzyme, together with its interacting partner MMADHC, directly to downstream enzymes involved in adenosylcob(III)alamin and methylcob(III)alamin biosynthesis. In addition to its dealkylase function, the enzyme also catalyse an entirely different decyanase reaction with cyanocob(III)alamin (cf. EC 1.16.1.6, cyanocobalamin reductase).