| 摘要 |
Method comprises (i) culturing a microbe which can produce pyranose-oxidase (PO) and belonging to Coriolus, Daedaleopsis, Gloeophyllum or Pleurotus, in a nutrient medium; and (ii) recovering PO from the microbial body. The microbes are e.g. Coriolus versicolor (IFO4937), Daedaleopsis styracina (IFO 4910), Gloeophyllum sepiarium Z-41 (NRRL 12506), Pleurotus ostreatus Z-64 (NRRL 12507), etc. The culture is pref. aerobic at 20-35 (25-30) deg.C at pH 3.0-8.0 (4.5-6.5) for 2-4 days. Thus prepd. PO is stable at pH 5.0-7.4 and has optimum pH at 6.2 and optimum temp. at 50 deg.C. The relative activity of PO for glucose, xylose and sorbose are 100, 3.4 and 2.6 respectively. By determing those substances formed H2O2 is determined by colourimetry. A kit composed of PO 0.5-15 U, peroxidase 2-10 U, colour-developing agent 5-20 mumol and buffer soln. 1-3 ml can be used for each determination. PO is the enzyme which catalyses the oxidising reactions of (a) glucose to glucosone, (b) xylose to xylosone, and (c) sorbose to 5-ketofructose forming H2O2, PO being useful for determining these substances. |
