Appearance : Light blue amorphous powder, lyophilized
Stability : Store at －20℃ (A decrease in activity of ca.20% may occur at 5℃ within 6 months.)
Molecular weight : 132,000, 140,000
Isoelectric point : between 6.0 and 7.8 , 8.2
Michaelis constant : 2.5×10－4M (Ascorbate)
Structure : 8 copper atoms per mol of enzyme
Inhibitors : cyanide, Na2S, diethyldithiocarbamate (Na)
Optimum pH : 5.6
Optimum temperature : approx. 30℃
pH Stability : pH 7.0－10.0 (25℃, 17hr)
Thermal stability : below 40℃ (pH 8.0, 30min)
Substrate specificity : This enzyme oxidizes ascorbic acid and several ascorbic derivatives.
使用
Ascorbate oxidase, from Cucurbita sp., may be used to study oxidative stress and heat stress response and tolerance. Also used in ascorbic acid assays to study the heat stress response of Arabidopsis and useful for enzymatic determination of ascorbic acid and for eliminating the interference of ascorbic acid in clinical analysis.
定義
An enzyme found in plant tissue that acts upon ascorbic acid in the presence of oxygen to produce dehydroascorbic acid.
一般的な説明
Ascorbate oxidase is a homodimeric enzyme, which comprises 552 amino acid residues per subunit (zucchini). It corresponds to a molecular mass of 70kDa per subunit. This enzyme is mainly found in plants, fungi and eubacteria.
