Sains Malaysiana 34(2): 125-128 (2005)

Penggunaan Enzim Tirosinase Pegun dalam Filem Sol-gel

untuk Pengesanan Fenol dengan Kaedah Optik

(The Use of Immobilised Tyrosinase Enzyme in

Sol-gel Film for Optical Phenol Detection)

Jaafar Abdullah, Musa Ahmad & Lee Yook Heng

Pusat Pengajian Sains Kimia dan Teknologi Makanan

Fakulti Sains dan Teknologi

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, D.E., Malaysia

Nadarajah Karuppiah & Hamidah Sidek

Pusat Alam Sekitar dan Teknologi Bioproses

SIRIM Berhad, No.1, Persiaran Dato' Menteri Seksyen 2

P.O. Box 7035, 40911 Shah Alam

Selangor, D.E., Malaysia

ABSTRAK

Biosensor optik berasaskan enzim tirosinase pegun dalam filem sol-gel untuk pengesanan fenol dibincangkan dalam kertas kerja ini. Teknik sapuan (smearing) telah digunakan untuk penyediaan filem tirosinasel sol-gel di atas penyokong slaid plastik. o-kuinon yang terhasil daripada tindak balas enzim tirosinase terhadap fenol akan berinteraksi dengan reagen 3-metil-2-benzotiazolinon hidrazon (MBTH) menghasilkan produk tambah kuinon-MBTH berwarna maron yang memberikan serapan pada panjang gelombang 490 nm. Julat kelinearan biosensor terhadap fenol adalah antara 0.031 mM hingga 0.25 mM dengan had pengesanan 0.003 mM. Nilai RSD untuk kajian fabrikasi biosensor optik ini adalah 8.8 %.

Kata kunci: Fenol, enzim tirosinase, filem sol-gel, optik

ABSTRACT

An optical biosensor based on immobilized tyrosinase in sol-gel film for phenol detection is described in this paper. The film of tyrosinase/sol-gel was prepared by smearing technique on a plastic slide support. The o-quinone resulted from the enzymatic oxidation of phenol was reacted with 3-methyl-2-benzothiazolinone hydrazone (MBTH) to produce a maroon colour adduct that can be observed at 490 nm. The linearity of the biosensor towards phenol was found to be in concentration range of 0.031 mM to 0.25 mM with detection limit of 0.003 mM. The RSD of the biosensor fabrication studies was 8.8 %.

Keywords: Phenol, tyrosinase enzyme, sol-gel film, optic

RUJUKAN/REFERENCES

Environmental Quality Act & Regulations. 1997. Detail on environmental quality act 1974 and regulation amendments from 1980 to May 1997. MDC Publishers Printers Sdn Bhd.

Espin, J.C., Tudela, J. & Garcia-Canovas, F. 1998. 4-­hydroxyanisole: The most suitable monophenolic substrate for determining spectrophotometrically the monophenolase activity of ploy phenol oxidase from fruits and vegetables. Analytical Biochemistry 259: 118-126.

Fenoll, L.G., Rodriguez-Lopez, J.N., Garcia-Molina, F., Garcia­Canovas, F. & Tudela, J. 2002. Michaelis constants of mushroom tyrosinase with respects to oxygen in the presence of monophenols and diphenols. The International Journal of Biochemistry and Cell Biology 34: 332-336.

Food Act 1983 & Food Regulations 1985. 1996. MDC Publishers Printers Sdn Bhd Kuala Lumpur.

Freire, R.S, Duran, N. & Kubota, L.T. 2002. Electrochemical biosensor-based devices for continuous phenols monitoring in environmental matrices. J. Braz. Chem. Soc.  vol. 13, No. 4: 456-462.

Paranjpe, P., Dutta, S., Karve, M., Padhye, S. & Narayanaswamy, R. 2001. A disposable optrode using tyrosinase films. Analytical Biochemistry 294: 102-107.

Russell, M. & Burton, S.G. 1999. Development and demonstration of an immobilised-polyphenol oxidase bioprobe for the detection of phenolic pollutants in water. Analytica Chimica Acta 389: 161-170.

Setti, L., Giuliani, S., Spinozzi, G. & Pifferi, P.G. 1999. Laccase catalyzed-oxidative coupling of 3-methyl 2-benzothiazolinone hydrazone and methoxyphenols. Enzyme and Microbial Technology 25: 285-289.

Vadgama, P. 1992. Designing biosensors. Chemistry in Britain (March): 249-252.

Wang, G., Xu, J.J., Ye, L.H., Zhu, J.J. & Chen, H.Y. 2002. Highly sensitive sensors based on the immobilization of tyrosinase in chitosan. Bioelectrochem. 57: 33-38.

Wu, L.Q., Chen, T., Wallace, K.K., Vazquez-Duhalt, R. & Payne, G.F. 2001. Enzymatic coupling of phenol vapors onto chitosan. Biotechnology and Bioengineering. 76 (4): 325-332.