ß-Galactosidase monitoring by a biosensor based on Clark electrode: Its optimization, characterization and application

PubMed ID: 18395435ß-Galactosidase is an hydrolase enzyme that catalyzes the hydrolysis of ß-galactosides into monosaccharides. Substrates of different ß-galactosidases include ganglioside GM1, lactosylceramides, lactose, and various glycoproteins. A novel aspect of the activity determination of ß-galactosidase was presented. A glucose oxidase biosensor based on Clark electrode was utilized in order to monitor ß-galactosidase. Immobilization of glucose oxidase was made by gelatin and glutaraldehyde as cross-linker. Several parameters such as glucose oxidase activity, gelatin amount, and glutaraldehyde percentage for cross-linking were optimized. The most important parameter, lactose concentration in working buffer was studied in detail. Optimum temperature, thermal stability, optimum pH, buffer system and its concentration effect on the biosensor system, repeatability, reproducibility, and storage and operational stabilities of the biosensor were identified. A linear detection range for ß-galactosidase was observed between 9.4 × 10-5 and 3.2 × 10-2 U/ml. Finally, ß-galactosidase activity in artificial intestinal juice was investigated by the biosensor and the results obtained were compared with a reference spectrophotometric method. © 2008 Elsevier B.V. All rights reserved.Canon Foundation for Scientific Research: 2004 FEN 002The authors are grateful to the financial supports of Ege University, Scientific Research Foundation (Grant No. 2004 FEN 002). -