preferred_name: a triacylglycerol + glycerol => a 1-acylglycerol + a 1,2-diacylglycerol
preferred_name_lc: a triacylglycerol + glycerol => a 1-acylglycerol + a 1,2-diacylglycerol
label: a triacylglycerol + glycerol => a 1-acylglycerol + a 1,2-diacylglycerol
label_lc: a triacylglycerol + glycerol => a 1-acylglycerol + a 1,2-diacylglycerol