Antimicrobial activity of a 48-kDa protease (AMP48) from Artocarpus heterophyllus latex

J. Siritapetawee, S. Thammasirirak*, W. Samosornsuk**

School of Biochemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima (Thailand)
*Protein and Proteomic Research Group, Department of Biochemistry, Faculty of Science, Khon Kaen University, Khon Kaen (Thailand)
*Department of Medical Technology, Faculty of Allied Health Sciences Faculty of Science, Thammasat University, Pathumthani (Thailand)

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• Phytomedicine

Background and Objective: Artocarpus heterophyllus (jackfruit) is a latex producing plant. Plant latex is produced from secretory cells and contains many intergradients. It also has been used in folk medicine. This study aimed to purify and characterize the biological activities of a protease from jackfruit latex.

Materials and Methods: A protease was isolated and purified from crude latex of a jackfruit tree by acid precipitation and ion exchange chromatography. The proteolytic activities of protein were tested using gelatin- and casein-zymography. The molecular weight and isoelectric point (pI) of protein were analysed by SDS/12.5% PAGE and 2D-PAGE, respectively. Antimicrobial activity of protein was analysed by broth microdilution method. In addition, the antibacterial activity of protein against Pseudomonas aeruginosa ATCC 27853 was observed and measured using atomic force microscopy (AFM) technique.

Results and Conclusions: The purified protein contained protease activity by digesting gelatin- and casein-substrates. The protease was designated as antimicrobial protease-48 kDa or AMP48 due to its molecular mass on SDS-PAGE was approximately 48 kDa. The isoelectric point (pI) of AMP48 was approximately 4.2. In addition, AMP48 contained antimicrobial activities by it could inhibit the growths of Pseudomonas aeruginosa ATCC 27853 and clinical isolated Candida albicans at minimum inhibitory concentration (MIC) 2.2 mg/ml and Minimum microbicidal concentration (MMC) 8.8 mg/ml. AFM image also supported the antimicrobial activities of AMP48 by the treated bacterial morphology and size were altered from normal.

Corresponding Author: Jaruwan Siritapetawee, Ph.D.; e-mail: jaruwan_siritape@yahoo.com

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