Co(I)-[glycine betaine-specific corrinoid protein] + glycine betaine + H(+) <=> methyl-Co(III)-[glycine betaine-specific corrinoid protein] + N,N-dimethylglycine
co(i)-[glycine betaine-specific corrinoid protein] + glycine betaine + h(+) <=> methyl-co(iii)-[glycine betaine-specific corrinoid protein] + n,n-dimethylglycine