Kinetic behaviour and stability of Escherichia coli ATCC27257 alkaline phosphatase immobilised in soil humates
✍ Scribed by María C Pilar; Natividad Ortega; Manuel Perez-Mateos; María D Busto
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 145 KB
- Volume
- 83
- Category
- Article
- ISSN
- 0022-5142
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Alkaline phosphatase (EC 3.1.3.1) extracted from Escherichia coli ATCC27257 was immobilised by co‐flocculation with soil humates in the presence of Ca^2+^. The effects of time, temperature, pH and concentration of enzyme and support on immobilisation were studied. Between 58 and 92% of the added phosphatase was strongly bound to the humates, depending on the conditions of immobilisation used. Some characteristics of the humate–phosphatase complexes and of the free enzyme were compared. The enzymatic complexes showed values of K~m~ (2.22 mM) and activation energy (33.4 kJ mol^−1^) similar to those of the free enzyme (2.00 mM and 27.6 kJ mol^−1^). The pH/activity profiles revealed no change in terms of shape or optimum pH (10.5) upon immobilisation of alkaline phosphatase. However, the immobilised enzyme showed maximal activity in the range of 80–100 °C, while the free enzyme had its highest activity at 60 °C. The thermal stability of alkaline phosphatase was enhanced by complexation to the soil humates.
© 2003 Society of Chemical Industry