4-Nitrophenyl butyrate

4-Nitrophenyl butyrate is a chromogenic substrate widely used in enzymology and biochemical research for the detection and characterization of esterase and lipase activity. Upon enzymatic hydrolysis, it releases the chromophore 4-nitrophenol, which can be converted to p-nitrophenoxide under alkaline conditions and quantified spectrophotometrically by monitoring its strong absorbance at approximately 405 nm. Due to its high sensitivity and convenient colorimetric readout, 4-nitrophenyl butyrate is commonly used in enzyme kinetics, inhibitor screening and studies of hydrolase activity. It is also used as an intermediate in organic synthesis and chemical research.