Arthrobacter ureafaciens

White amorphous powder.

More than 80 units/mg protein for N-Acetylneuraminyllactose (NANA-lactose).
More than 20 units/mg protein for bovine submaxillary mucin. [at pH 5.0]
More than 40 units/mg protein for Colominic Acid. [at pH 4.5]
More than 60 units/mg protein for bovine brain ganglioside. [at pH 4.0]

One unit is the amount of enzyme required to liberate 1 µmol of N-Acetylneuraminic Acid (NANA) per minute at pH 5.0 at 37°C, using N-Acetylneuraminyllactose as a substrate.

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

Enzyme activities mentioned below cannot be detected. 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 and N-Acetyl-β-mannosaminidase.

Molecular weight	---	Approx. 52,000 Da (gel filtration, SDS-PAGE)
Optimum pH	---	3.8 ~ 4.4 ( for bovine brain ganglioside )
pH stability	---	3.5 ~ 10.0
Thermal stability	---	below 60°C (pH 5.0, 20 min)
Substrate specificity	---	Isozyme S cleaves α(2 → 3), α(2 → 6) and α(2 → 8) linkages of N-Acetylneuraminic Acid in glycoconjugates. In the absence of detergents and calcium ion, the enzyme hydrolyzes N-Acetylneuraminosyl moiety of polysialogangliosides and produces monosialoganglioside GM1, while in the presence of detergents ( Na-cholate, Triton X-100 etc. ), GM1 is further desialylated to asialoganglioside GA1. the character of the enzyme is similar to Vibrio cholerae Neuraminidase except requirement of Ca2+ in the latter.