武汉云克隆科技股份有限公司

Sphingomyelin phosphodiesterase 1 (SMPD1), also known as acid sphingomyelinase (ASM), belongs to the sphingomyelin phosphodiesterase family. The protein Converts sphingomyelin to ceramide. ASM also has phospholipase C activities toward 1,2-diacylglycerolphosphocholine and 1,2-diacylglycerolphosphoglycerol.
Thus, the recombinant human ASM activity was measured by its ability to hydrolyze 2-N-Hexadecanoylamino-4-nitrophenylphosphorylcholine (HDA-PC) to p-Nitrophenol. The reaction was performed in 50 mM MES, 0.5 µM ZnCl2, pH 7.5 ( Assay Buffer), initiated by addition 50 μL of various concentrations of ASM (diluted with Assay Buffer) to 50 µL of 1 mM Substrate HDA-PC ( 50 mM stock solution in methanol, diluted with Assay Buffer). Incubated at room temperature for 20 minutes in the dark, then read at a wavelength of 405 nm.

One unit of enzyme activity is defined as the 1μg of enzyme required to convert 1pmol of HDA-PC to p-Nitrophenol in 1min at 37°C. The specific activity of recombinant human ASM is >1000 pmol/min/µg.