Monopalmitin is a glycerol esterified fatty acid, monoacylglycerol, found in lipid structures such as ceramides. Monopalmitin may be used as a substrate for the identification and differentiation of enzymes that hydrolyze or transfer monoacylglycerols such as neuropathy target esterase(s) and monoacylglycerol acyltransferase(s) (MAG). Monopalmitin is a glycerol esterified fatty acid, monoacylglycerol, found in lipid structures such as ceramides. Monopalmitin may be used as a substrate for the identification and differentiation of enzymes that hydrolyze or transfer monoacylglycerols such as neuropathy target esterase(s) and monoacylglycerol acyltransferase(s) (MAG).