Preparation and Characterization of Cadaverine Sensitive Nylon Threads

We prepared catalytically active nylon threads, containing immobilized amine oxidase from pea seedlings for the application in biosensor systems as a selective biorecognition element for the detection of cadaverine (1,5-diaminopentane). The immobilization of the enzyme onto nylon threads, treated before enzyme binding consecutively with dimethyl sulfate and glutaraldehyde, resulted in threads with amine oxidase activity of (4.6 +/- 0.4) x 10(-4) IU/cm. The enzyme-containing threads enabled multiple and continuous measurements of cadaverine during 1 month with no detectable loss of activity. The unused threads retained their full activity at 4 C for 3 months; after that date the activity began to decrease slowly. The KM values of the soluble and immobilized amine oxidase towards cadaverine were determined with an oxygen sensor and were 1.41 +/- 0.17 mmol/l for soluble, and 0.60 +/- 0.06 mmol/l for immobilized enzyme.