The Journal of Biological Physics and Chemistry


Volume 7, Number 2, p.p. 65–68

In situ monitoring of adsorbed enzyme activity

M.G. Cacace1,2,* and J.J. Ramsden3,4

1 National Research Centre for Germinal Cells, Via Tommaso Pendola 62, 53100 Sienna, Italy
2 Institute for the Study of Nanostructured Materials, CNR, Via P. Gobetti 101, 40129 Bologna, Italy
3 Department of Biophysical Chemistry, Biozentrum, 4056 Basle, Switzerland
4 Department of Materials, Cranfield University, Bedfordshire, MK43 0AL, UK

The activity of an adsorbed urease monolayer is rapidly and conveniently determined in situ by monitoring refractive index shifts in the vicinity of the protein layer due to the change in selective dispersion of a pH indicator responding to the enzymatic decomposition of urea to ammonia. An elementary treatment of the optical and hydrodynamic phenomena is given for deriving the enzyme turnover number.

Keywords: enzyme immobilization, optical waveguides, dispersion, urease, carminic acid

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