label: a lipid IVA + a 1,2-diacyl-sn-glycero-3-phosphocholine = a lipid IVB + a 2-acyl-sn-glycero-3-phosphocholine
label_lc: a lipid iva + a 1,2-diacyl-sn-glycero-3-phosphocholine = a lipid ivb + a 2-acyl-sn-glycero-3-phosphocholine