产品信息

• 产品组分信息

  本产品提供以下试剂或组分：

  NEB #	名称	组分货号	储存温度	数量	浓度
  P0757S     -20       p-Nitrophenyl Phosphate (PNPP) P0757SVIAL -20 1 x 1 ml 500 mM
  P0757L     -20       p-Nitrophenyl Phosphate (PNPP) P0757SVIAL -20 5 x 1 ml 500 mM

• 特性和用法

  分子量

  理论上的: 461.4 daltons

• 注意事项

  1. Store protected from light.
  2. Protein Phosphatase Assay: The PNPP phosphatase activity assay is very simple, non-expensive, and routinely used for the unit determination of all NEB protein phosphatases. PNPP has apparent Km values for protein phosphatases in the range of 0.5 -10 mM (2-5).

     The PNPP phosphatase activity is assayed in a reaction mixture (50 μl) containing 50 mM PNPP and a protein phosphatase buffer supplemented with additional components when required. The reaction is initiated by addition of enzyme and quenched after 5-10 minutes by addition of 1 ml of 1 N NaOH (or 1 ml of 0.5 M EDTA for Mn2+-dependent protein phosphatases, Lambda PP and PP1). The amount of product, p-nitrophenol, is determined by reading the absorbance at 405 nm and using a molar extinction coefficient of 18,000 M-1 cm-1 (16,000 M-1cm-1 for 0.5 M EDTA) (1, 3). 

     One unit of the protein phosphatase activity is defined as the amount of enzyme that hydrolyzes 1 nanomole of PNPP in one minute at 30°C in a total reaction volume of 50 μl under standard reaction condition. 

     To estimate the protein phosphatase activity accurately it is essential to ensure linear kinetics of dephosphorylation. 

• 参考文献

  1. MacKintosh, C. (1993). In D.G. Hardie (Ed.). Protein Phosphorylation: A Practical Approach. 221. New York: IRL Press.
  2. Zhuo, S. et al. (1993). J. Biol. Chem.. 268, 17754-17761.
  3. Zhang, Z.-Y. et al. (1992). J. Biol. Chem.. 267, 23759-23766.
  4. Pot, D.A. et al. (1991). J. Biol. Chem.. 266, 19688-19696.
  5. Takai, A. and Mieskes, G. (1991). Biochem. J.. 275, 233-239.