title: Optical biosensor consisting of glutathione-S-transferase for detection of captan.
abstract: The optical biosensor consisting of a glutathione-S-transferase (GST)-immobilized gel film was developed to detect captan in contaminated water. The sensing scheme was based on the decrease of yellow product, s-(2,4-dinitrobenzene) glutathione, produced from substrates, 1-chloro-2,4-dinitrobenzene (CDNB) and glutathione (GSH), due to the inhibition of GST reaction by captan. Absorbance of the product as the output of enzyme reaction was detected and the light was guided through the optical fibers. The enzyme reactor of the sensor system was fabricated by the gel entrapment technique for the immobilized GST film. The immobilized GST had the maximum activity at pH 6.5. The optimal concentrations of substrates were determined with 1 mM for both of CDNB and GSH. The optimum concentration of enzyme was also determined with 100 microg/ml. The activity of immobilized enzyme was fairly sustained during 30 days. The proposed biosensor could successfully detect the captan up to 2 ppm and the response time to steady signal was about 15 min.
authors.affiliation: Department of Chemical Engineering, Sogang University, CPO Box 1142, Seoul 100-611, South Korea. jwchoi@ccs.sogang.ac.kr
authors.forename: Jeong-Woo
authors.initials: JW
authors.lastname: Choi
authors.forename: Young-Kee
authors.initials: YK
authors.lastname: Kim
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Song
authors.forename: In-ho
authors.initials: IH
authors.lastname: Lee
authors.forename: Won-Hong
authors.initials: WH
authors.lastname: Lee
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation* / Q000379:methods; D002215:Captan / Q000032:analysis* / Q000737:chemistry*; D004789:Enzyme Activation; D004795:Enzyme Stability; D004800:Enzymes, Immobilized / Q000737:chemistry; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation / Q000379:methods*; D005982:Glutathione Transferase / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D055100:Optical Fibers; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013057:Spectrum Analysis / Q000379:methods*
chemical_list: D004800:Enzymes, Immobilized; D005982:Glutathione Transferase; D002215:Captan