Enzymatic and biochemical characterization of Bungarus sindanus snake venom acetylcholinesterase

Ahmed M (1), Latif N (2), Khan RA (1), Ahmad A (1), Rocha JBT (2), Mazzanti CM (2), Bagatini MD (2), Morsch VM (2), Schetinger MRC (2)

(1) Department of Biotechnology, University of Science and Technology, Bannu, Kyber Pakhtunkhwa, Pakistan; (2) Department of Biochemistry and Toxicology, Center of Natural and Exact Sciences, Federal University of Santa Maria, Santa Maria, Rio Grande do Sul State, Brazil.

Abstract: This study analyses venom from the elapid krait snake Bungarus sindanus, which contains a high level of acetylcholinesterase (AChE) activity. The enzyme showed optimum activity at alkaline pH (8.5) and 45°C. Krait venom AChE was inhibited by substrate. Inhibition was significantly reduced by using a high ionic strength buffer; low ionic strength buffer (10 mM PO4 pH 7.5) inhibited the enzyme by 1. 5mM AcSCh, while high ionic strength buffer (62 mM PO4 pH 7.5) inhibited it by 1 mM AcSCh. Venom acetylcholinesterase was also found to be thermally stable at 45°C; it only lost 5% of its activity after incubation at 45°C for 40 minutes. The Michaelis-Menten constant (Km) for acetylthiocholine iodide hydrolysis was found to be 0.068mM. Krait venom acetylcholinesterase was also inhibited by ZnCl2, CdCl2, and HgCl2 in a concentrationdependent manner. Due to the elevated levels of AChE with high catalytic activity and because it is more stable than any other sources, Bungarus sindanus venom is highly valuable for biochemical studies of this enzyme.

Key words: acetylcholinesterase, inhibition, krait, ionic strength, acetylthiocholine iodide, Bungarus sindanus, snake venom.

ACKNOWLEDGEMENTS

The authors are grateful to the Academy of Sciences for the Developing World (TWAS) and the Higher Education Commission of Pakistan for the financial support.

COPYRIGHT

© CEVAP 2012

SUBMISSION STATUS

Received: December 20, 2012.

Accepted: March 9, 2012.

Abstract published online: March 23, 2012.

Full paper published online: May 31, 2012.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

FINANCIAL SOURCE

The Academy of Sciences for the Developing World (TWAS) and the Higher Education Commission of Pakistan provided the financial grants.

CORRESPONDENCE TO

Mushtaq Ahmed, Department of Biotechnology, University of Science and Technology, Bannu, Khyber Pakhtunkhwa, Pakistan. Phone: +92928633425. Email: mushtaq213@yahoo.com.