label: a sphingomyelin + a 1,2-diacylglycerol => 1,2-diacyl-glycero-3-phosphocholine + an N-acylsphing-4-enine
label_lc: a sphingomyelin + a 1,2-diacylglycerol => 1,2-diacyl-glycero-3-phosphocholine + an n-acylsphing-4-enine