Name: Xantine: oxygen oxidoreductase
Appearance: Reddish brown amorphous powder, lyophilized
Activity: Grade II, 10U/mg-solid or more
Contaminants: Catalase ≤ 5.0 %, Adenosine deaminase ≤ 1.0×10-3 %, Uricase ≤ 1.0×10-3 %, Phosphatase ≤ 1.0×10-3 %, Purine-nucleoside phosphorylase ≤ 5.0×10-3 %
Stabilizers: Sodium glutamate, BSA
Stabilit:y Stable at – 20°C for at least 12 months
Molecular weight: approx. 160,000
Isoelectric point: 4.0 ± 0.1
Michaelis constants: 4.5×10-5M (Xanthine), 7.6×10-5M (Hypoxanthine)
Inhibitors: Reducing agents, Hg2+, Ag+,MIA
Optimum pH: 7.5 – 8.0
Optimum temperature: 65°C
pH Stability: pH 6.5 – 9.0 (25°C, 15hr)
Thermal stability: below 55°C (pH 8.0, 30min)
EC # 1.1.3.22