Origin

Arthrobacter ureafaciens

Reaction

Sialyl compound → Sialic acid + Asialocompound

Appearance

White amorphous powder.

Activity

More than 50 units/mg protein for N-acetylneuraminyllactose (NANA-lactose).

Unit definition

One unit is the amount of enzyme required to liberate 1 μmol of N-acetylneuraminic acid (NANA) per minute at pH5.0 at 37 ºC. ※1

Storage

Stable for one year when stored below 5 ºC.
For prolonged storage, keep at -20 ºC.

Contaminants

Enzyme activities mentioned below cannot be detected.※2
Protease , N-Acetylneuraminic acid aldolase,
Glycosidase such as

α-Glucosidase	β-Glucosidase	α-Galactosidase
β-Galactosidase	α-Mannosidase	α-Fucosidase
N-Acetyl-α-glucosaminidase		N-Acetyl-β-glucosaminidase
N-Acetyl-α-galactosaminidase		N-Acetyl-β-galactosaminidase
N-Acetyl-α-mannosaminidase		N-Acetyl-β-mannosaminidase

Properties ※3-※4

Molecular weight	Approx. 52,000 Da, 66,000 Da and 88,000 Da (gel filtration, SDS-PAGE)
Optimum pH	4.5–5.5 (NANA-lactose as a substrate)
pH stability	4.5–9.5
Thermal stability	below 60 ºC (pH5.0, 20 min)
Substrate specificity	The α-ketosidic linkage of N-glycolylneuraminic acid (NGNA) can be hydrolyzed as well as that of NANA. This enzyme cleaves α(2→3), α(2→6) and α(2→8) linkages of N-acetylneuraminic acid in glycoconjugates. The acivity is independent on Ca2+ and is not inhibited by EDTA, which is in striking contrast to Vibrio cholerae neuraminidase, and is not or slightly inhibited by inhibitors such as monoiodoacetate, p-chloromercuribenzoate and HgCl2, which is in striking contrast to Clostridium perfringens neuraminidase.

Assay method

Standard assay system is composed of 50 μl of substrate solution (4 mg/ml, NANA-lactose), 50 μl of 200 mM acetate buffer (pH5.0) and 100 μl of enzyme solution. Reaction is carried out at 37 ºC for 10 minutes and NANA liberated is determined by thiobarbituric acid (TBA) method.※1-※4

References

1. ※1. L. Warren, J. Biol. Chem., 234, 1971 (1959)
2. ※2. Y. Uchida, Y. Tsukada and T. Sugimori, J. Biochem., 82, 1425 (1977)
3. ※3. Y. Uchida, Y. Tsukada and T. Sugimori, J. Biochem., 86, 1573 (1979)
4. ※4. Y. Ohta, Y. Tsukada and T. Sugimori, J. Biochem., 106, 1086 (1989)

Package

5 unit, 100 units