5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase

In enzymology, a 5-methyltetrahydropteroyltriglutamate-homocysteine S-methyltransferase is an enzyme that catalyzes the chemical reaction


 * 5-methyltetrahydropteroyltri-L-glutamate + L-homocysteine $$\rightleftharpoons$$ tetrahydropteroyltri-L-glutamate + L-methionine

Thus, the two substrates of this enzyme are 5-methyltetrahydropteroyltri-L-glutamatic acid and L-homocysteine, whereas its two products are tetrahydropteroyltri-L-glutamatic acid and L-methionine.

This enzyme belongs to the family of transferases, specifically those transferring one-carbon group methyltransferases. The systematic name of this enzyme class is 5-methyltetrahydropteroyltri-L-glutamate:L-homocysteine S-methyltransferase. Other names in common use include tetrahydropteroyltriglutamate methyltransferase, homocysteine methylase, methyltransferase, tetrahydropteroylglutamate-homocysteine transmethylase, methyltetrahydropteroylpolyglutamate:homocysteine methyltransferase, cobalamin-independent methionine synthase, methionine synthase (cobalamin-independent), and MetE. This enzyme participates in methionine metabolism. It has 2 cofactors: orthophosphate, and zinc.

Structural studies
As of late 2007, 9 structures have been solved for this class of enzymes, with PDB accession codes, , , , , , , , and.