Mahira PARVEEN, Santosh KUMAR, Pramila SINGH

Kinetic analysis of the in vivo inhibition of liver AChE in air breathing fish Clarias batrachus (Linnaeus,1758)

Karaciğerdeki AChE dağılımından dolayı, nörotoksik pestisit karbaril ile zıt bir etkileşim gözlenmektedir. Bu çalışma, karbaril'in karaciğer AChE üzerindeki toksik etkilerini değerlendirmek amacıyla gerçekleştirilmiştir. Çalışmada, balıklar 96 saat boyunca karbarilin subtotal konsantrasyonuna maruz bırakılmış ve karaciğerdeki AChE enzim kinetiği üzerindeki etkileri araştırılmıştır. Subletal konsantrasyon 0.04 ppm olarak, karbarilin LC50 değeri bazında (0.137 ppm, Ramana Rao vd., 1991) alınmıştır. Karaciğer çıkartılmış ve asetilkolinesteraz enzim kinetiği kontrol ve deney gruplarında gözlenmiştir. AChE için Km, $1.46x10^{-3}$ M olarak tespit edilmiştir. Karbaril uygulamasından sonra Km artarak $2.0 x 10^{-3}$ M değerine yükselmiştir. Karbaril uygulanmış ve kontrol karaciğeri için Vmax 0.9A /mg protein/30 min değerinde sabit kalmıştır. Kontrol ve karbamat uygulanmış balık dokularındaki AChE kinematik çalışması, karbaril inhibisyonunun rekabetçi doğasını göstermiştir.

Anahtar Kelimeler:

Clarias batrachus, karaciğer, zararlı öldürücü kalıntıları, kinetik, engelleme, balık, karbaril

Clarias batrachus (Linnaeus,1758) karaciğerinde AChE inhibisyonunun in vivo kinetik analizi

Because of the distribution of AChE in liver it is affected adversely by the neurotoxic pesticide carbaryl. To evaluate the toxic effects of carbaryl on liver AChE , the work is carried out. In the present investigation, the fishes were intoxicated with sublethal concentration of carbaryl for 96 hours period and its effects were studied on AChE enzyme kinetics in liver. Fishes were exposed to carbaryl for 96 hours period. The sublethal concentration was taken as 0.04 ppm on the basis of LC of carbaryl i.e. 0.137 ppm (Ramana Rao et al 1991). The liver was removed and acetylcholinesterase enzyme kinetics was observed in control and experimental groups. The Km for AChE in control liver was observed as $1.46x 10^{-3}$ M. After the carbaryl treatment the Km was increased and became $2.0 x 10^{-3}$ M. The Vmax for carbaryl treated and control liver was constant at 0.9A /mg protein/30 min. Kinetic study of AChE in control and carbamate exposed fish tissues show competitive nature of inhibition by carbaryl.

Keywords:

Clarias batrachus, liver, pesticide residues, kinetics, inhibition, fishes, carbaryl,

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