Abstract:

An antimicrobial protein was isolated and purified from the seed kernels of Ginkgo biloba and its antimicrobial
activity was analyzed. Ginkgo biloba seed protein (GBSP) was purified by ammonium sulfate precipitation, dialysis, DEAEcellulose
DE52 ion-exchange and Sephadex G-75 gel filtration through bioassay-guided method. A protein fraction named
GBSPⅠ-A possessing antimicrobial activity, was obtained. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis
(SDS-PAGE) analysis suggested that the protein was homogeneous and its apparent molecular mass was 42.80 kD. The
results of chromatographic identification by Superdex G-75 and HPGPC showed a single and symmetrical peak with a
molecular weight of 39.32 kD. The protein exhibited potent antimicrobial activity against K. pneumoniae, S. aureus,
T. delbrueckii, and A. niger with minimum inhibitory concentrations (MIC) of 20, 20, 20, and 12 mg/mL, respectively.
This study could provide a theoretical basis for the discovery of a new antibacterial protein and the development of
food preservatives.

Key words: Ginkgo biloba seed protein (GBSP), isolation and purification, antimicrobial activity, molecular weight