Origin
Escherichia coli
Reaction
N-Acetylneuraminate 
N-Acetyl-D-mannosamine + pyruvate
Appearance
White amorphous powder.
Activity
More than 30 units/mg protein.
Unit definition
One unit is the amount of enzyme required to liberates 1 μmol of N-acetylmannosamine (or pyruvic acid) per minute at pH7.7 at 37 ºC, using N-acetylneuraminic acid (NANA) as a substrate.
Storage
Stable for one year when stored below 5 ºC.
For prolonged storage, keep at -20 ºC.
Contaminants
Free from NADH oxidase.
Properties※1-※2
| Molecular weight | Approx. 98,000 Da (gel filtration) |
|---|---|
| Optimum pH | 7.5–8.0 |
| pH stability | 6.0～9.0 |
| Thermal stability | below 65 ºC (pH7.0, 20 min) |
| Substrate specificity | N-glycolylneuraminic acid (NGNA) is cleaved as well as NANA. Km = 3.6 mM (NANA), 4.3 mM (NGNA) |
Uses
Enzymatic determination of sialic acid and enzymatic syntheses of novel sialic acid derivatives.
Assay method
Standard assay system is composed of 50 μl of NANA solution (40 μmol/ml, pH7.0), 50 μl of 200 mM phosphate buffer (or Tris-HCl buffer, pH7.5) and 100 μl of enzyme solution. Reaction is carried out at 37 ºC for 10 minutes and N-acetylmannosamine is determined with the Morgan-Elson test modified by Brunetti et al.※3
References
- ※1. Y. Uchida, Y. Tsukada and T. Sugimori, J. Biochem.,96, 507 (1984)
- ※2. Y. Ohta, M. Shimosaka, K. Murata, Y. Tsukada and A. Kimura, Appl. Microbiol. Biotechnol.,24, 386 (1986)
- ※3. P. Brunetti, G. W. Jourdian and S. Roseman, J. Biol. Chem.,237, 2447 (1962)
Package
1 unit, 5 units
