9027-60-5

Purify the aldolase by extraction with H2O, protamine precipitation, (NH4)2SO4 fractionation, Me2CO precipitation, acid treatment at pH 5.7 and precipitation at pH 4.5. The equilibrium constant for pyruvate + n-acetyl-D-mannosamine N-acetylneuraminidate at 37o is 0.64. The Km for N-acetylneuraminic acid is 3.9mM in phosphate at pH 7.2 and 37o. [Comb & Roseman Methods Enzymol 5 391 1962.] The enzyme from hog kidney (cortex) has been purified 1700-fold by extraction with H2O, protamine sulfate precipitation, (NH4)2SO4 fractionation, heating between 60-80o, a second (NH4)2SO4 fractionation and starch gel electrophoresis. The Km for N-acetylneuraminic acid is 1.5mM. [Brunetti et al. J Biol Chem 237 2447 1962.]