4-Nitrophenyl stearate

4-Nitrophenyl stearate is a chromogenic long-chain fatty acid ester substrate widely used in enzymology and biochemical research for the characterization of lipase activity (less esterase activity). Upon enzymatic hydrolysis, it releases 4-nitrophenol, which can be converted to p-nitrophenoxide under alkaline conditions and quantified spectrophotometrically by monitoring its absorbance at approximately 405 nm. Due to its highly hydrophobic stearate chain, 4-nitrophenyl stearate is particularly suitable for studying enzymes involved in the hydrolysis of long-chain lipid esters, including microbial, pancreatic, and recombinant lipases. It is also used in kinetic studies, enzyme screening, and characterization of lipid-metabolizing enzymes.