methyl-Co(III)-[tetramethylammonium-specific corrinoid protein] + trimethylamine => tetramethylammonium + Co(I)-[tetramethylammonium-specific corrinoid protein] + H(+)
methyl-co(iii)-[tetramethylammonium-specific corrinoid protein] + trimethylamine => tetramethylammonium + co(i)-[tetramethylammonium-specific corrinoid protein] + h(+)