Catalyzes methyl transfer from S-methylmethionine to homocysteine. The highest preference is for DL-homocysteine >> DL-cysteine. Has no selenocysteine methyltransferase activity. L-homocysteine + S-methyl-L-methionine = H(+) + 2 L-methionine Inhibited by L-methionine. Optimum pH is 7.2. Expressed in roots, young leaves, florets and flowers. Not detected in old leaves. Not induced by selenate or selenite. Up-regulated by sulfate. Not affected by the status of methionine, s-methylmethionine or homocysteine, or by cadmium.