a 1,2-diacyl-sn-glycero-3-phospho-N-methylethanolamine + S-adenosyl-L-methionine => a 1,2-diacyl-sn-glycero-3-phospho-N,N-dimethylethanolamine + S-adenosyl-L-homocysteine + H(+)
a 1,2-diacyl-sn-glycero-3-phospho-n-methylethanolamine + s-adenosyl-l-methionine => a 1,2-diacyl-sn-glycero-3-phospho-n,n-dimethylethanolamine + s-adenosyl-l-homocysteine + h(+)