摘要 |
The activity of alkaline phosphatase in aqueous solution, especially in reconstituted serum, is kept constant by adding to the phosphatase-containing solution Mn2+ or Cd2+ ions, preferably to an end concentration of 0.05 to 0.5 mMol/liter of Mn2+ or 0.05 to 0.1 mMol/liter of Cd2+. Control serums comprising the Mn2+ and/or Cd2+ ions in human or animal serum or serum-like compositions are also provided. |