2.1.1.90	5-hydroxybenzimidazolylcobamide	-	
2.1.1.90	5-hydroxybenzimidazolylcobamide	corrinoid protein	
2.1.1.90	5-hydroxybenzimidazolylcobamide	3-4 molecules bound, acting as methyl acceptor	
2.1.1.90	corrinoid	the enzyme only binds the methyl group of methanol when the cobalt atom of its corrinoid prosthetic groups is present in the highly reduced Co(I) state. Formation of this redox state requires H2, hydrogenase, methyltransferase activation protein, and ATP. Purified enzyme contains 1.7 corrinoids per enzyme with cobalt in the fully oxidized Co(III) state. Water and N-3 of the 5-hydroxybenzimidazolyl base serve as the upper and lower ligands, respectively. Reduction to the Co(II) level is accomplished by H2 and hydrogenase. The cob(II)amide of the enzyme has the base coordinated at this stage. Subsequent addition of methyltransferase activation protein and ATP results in the formation of base-uncoordinated Co(II) enzyme