preferred_name: 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phospho-N-methylethanolamine + S-adenosyl-L-methionine <=> 1,2-di-(9Z,12Z-octadecadienoyl)-sn-glycero-3-phospho-N,N-dimethylethanolamine + S-adenosyl-L-homocysteine + H(+)