Amperometric bi-enzyme based biosensor for the detection of lactose--characterization and application.
Based on the glucose oxidase-beta-galactosidase sequence an enzyme probe for the specific determination of lactose has been developed. beta-Galactosidases from different sources have been compared, the sensor containing beta-galactosidase from Curvularia inaequalis has been characterized in respect of optimal pH, enzyme loading, apparent activity and functional stability. The response of the bi-enzyme probe depends linearly on lactose concentration between 0.02 and 3.00 mmol dm-3. The application to different milk and foodstuff samples resulted in good correlations toward enzymatic photometric (y = (0.956x-1.67) mmol dm-3) and infrared detection (y = (1.0772x-0.3909)%). Using a measuring frequency of 100 h-1 the serial imprecision is about 2% for diluted milk, urine, or foodstuff samples.
Academy of Sciences of the GDR, Central Institute of Molecular Biology, Berlin-Buch.
D
D
Pfeiffer
E V
EV
Ralis
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A
Makower
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FW
Scheller
D000818:Animals; D015374:Biosensing Techniques; D002417:Cattle; D004800:Enzymes, Immobilized / Q000378:metabolism*; D005504:Food Analysis; D005949:Glucose Oxidase / Q000378:metabolism*; D007700:Kinetics; D007785:Lactose / Q000032:analysis* / Q000652:urine; D008892:Milk / Q000737:chemistry*; D001616:beta-Galactosidase / Q000378:metabolism*
D004800:Enzymes, Immobilized; D005949:Glucose Oxidase; D001616:beta-Galactosidase; D007785:Lactose