methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase activity
Catalysis of the reaction: a tetrahydrofolate + a [methyl-Co(III) corrinoid Fe-S protein] = an N5-methyl-tetrahydrofolate + a [Co(I) corrinoid Fe-S protein].
GO:0008168
methyltransferase activity
is_a