B12-dependent methyl-H4-folate homocysteine methyltransferase in euglena gracilis

Abstract

Partially purified extracts of Euglena gracilis catalyze synthesis of methionine from methyl-H₄-folate and homocysteine. A reducing system and S-adenosyl-methionine are required for full activity, thus indicating that the enzyme involved is the B₁₂-dependent methyl-H₄-folate homocysteine methyltransferase.