sterol 24-C-methyltransferase activity

Catalysis of the reaction: S-adenosyl-L-methionine + 5-alpha-cholest-8,24-dien-3-beta-ol = S-adenosyl-L-homocysteine + 24-methylene-5-alpha-cholest-8-en-3-beta-ol.

24-sterol C-methyltransferase activity, S-adenosyl-4-methionine:sterol Delta(24)-methyltransferase activity, S-adenosyl-4-methionine:sterol delta24-methyltransferase activity, S-adenosyl-L-methionine:Delta(24(23))-sterol methyltransferase activity, S-adenosyl-L-methionine:Delta24(23)-sterol methyltransferase activity, S-adenosyl-L-methionine:zymosterol 24-C-methyltransferase activity, SMT1 activity, delta(24)-methyltransferase activity, delta(24)-sterol C-methyltransferase activity, delta(24)-sterol methyltransferase activity, delta24-methyltransferase activity, delta24-sterol methyltransferase activity, phytosterol methyltransferase activity, sterol 24-C-methyltransferase activity, zymosterol-24-methyltransferase activity