Purification and antibacterial activities of an L-amino acid oxidase from king cobra (Ophiophagus hannah) venom

Phua CS (1), Vejayan J (2), Ambu S (1), Ponnudurai G (1), Gorajana A (1)

(1) Faculty of Medicine and Health, International Medical University, Kuala Lumpur, Malaysia; (2) School of Medicine and Health Sciences, Monash University, Sunway Campus, Selangor Darul Ehsan, Malaysia.

Abstract: Some constituents of snake venom have been found to display a variety of biological activities. The antibacterial property of snake venom, in particular, has gathered increasing scientific interest due to antibiotic resistance. In the present study, king cobra venom was screened against three strains of Staphylococcus aureus [including methicillin-resistant Staphylococcus aureus (MRSA)], three other species of gram-positive bacteria and six gram-negative bacteria. King cobra venom was active against all the 12 bacteria tested, and was most effective against Staphylococcus spp. (S. aureus andS. epidermidis). Subsequently, an antibacterial protein from king cobra venom was purified by gel filtration, anion exchange and heparin chromatography. Mass spectrometry analysis confirmed that the protein was king cobra L-amino acid oxidase (Oh-LAAO). SDS-PAGE showed that the protein has an estimated molecular weight of 68 kDa and 70 kDa under reducing and non-reducing conditions, respectively. The minimum inhibitory concentrations (MIC) of Oh-LAAO for all the 12 bacteria were obtained using radial diffusion assay method. Oh-LAAO had the lowest MIC value of 7.5 μg/mL against S. aureus ATCC 25923 and ATCC 29213, MRSA ATCC 43300, and S. epidermidis ATCC 12228. Therefore, the LAAO enzyme from king cobra venom may be useful as an antimicrobial agent.

Key words: L-amino acid oxidase, king cobra, antibacterial activity, Ophiophagus hannah.

ACKNOWLEDGEMENTS

The authors would like to thank the International Medical University of Malaysia for the support.

COPYRIGHT

© CEVAP 2012

SUBMISSION STATUS

Received: November 17, 2011.

Accepted: February 17, 2012.

Abstract published online: March 6, 2012.

Full paper published online: May 31, 2012.

CONFLICTS OF INTEREST

The authors declare no conflicts of interest.

FINANCIAL SOURCE

The International Medical University, Malaysia, provided the financial grants.

ETHICS COMMITTEE APPROVAL

The present study was approved by the 30th IMU Joint-Committee of the Research and Ethics Committee under the identification number BMSc I-01/2010, International Medical University of Malaysia.

CORRESPONDENCE TO

Chun Seng Phua, Faculty of Medicine and Health, International Medical University, Kuala Lumpur, Malaysia. Phone: +603 22742136. Email: chunsengphua@yahoo.com.