African Journal of
Biochemistry Research

  • Abbreviation: Afr. J. Biochem. Res.
  • Language: English
  • ISSN: 1996-0778
  • DOI: 10.5897/AJBR
  • Start Year: 2007
  • Published Articles: 425

Full Length Research Paper

Alpha-amylase inhibitor of amadumbe (Colocasia esculenta): Isolation, purification and selectivity toward α- amylases from various sources

R. McEwan1*, R. P. Madivha1, T. Djarova1, O. A. Oyedeji2 and A. R. Opoku1
1Department of Biochemistry and Microbiology, University of Zululand, P/B X1001, KwaDlangezwa 3886, South Africa. 2Department of Chemistry, University of Zululand, P/B X1001 KwaDlangezwa 3886, South Africa.
Email: [email protected].

  •  Accepted: 25 June 2010
  •  Published: 30 September 2010


Two proteins (A-1 and B-2) with a-amylase inhibitor activity  were extracted and partially purified from Colocasia esculenta tubers through 80% ammonium sulphate fractionation, ion-exchange chromatography on DEAE-Sephacel and gel-chromatography on Sephadex G-100. The molecular weight of A-1 and B-2 were estimated to be about 17000 and 19000 daltons, respectively. The inhibitors inactivated a-amylases of animal origin, but had no effect on fungal amylase. Inhibitor A-1 also exhibited activity towards plant amylases, while inhibitor B-2 has no activity on plant amylases. Inhibitor A-1 was the most active against human salivary amylase at pH 6. Inhibitor A-1 was completely destroyed at temperatures above 50°C; while inhibitor B-2 was stable up to 70°C.


Key words:  a-amylase inhibitor, amadumbe, Colocasia esculenta, diabetes, obesity.