Purification,Characterization and N‐terminal Sequence Analysis of Betel Leaf (Piper betle) Invertase |
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Authors: | Md Murad Hossain Farzana Pervin Nurul Absar |
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Institution: | 1. Current address: Department of Cell Biology, Institute of Nephrology, Niigata University, 1‐757 Asahimachi‐dori, Niigata 951‐8510, Japan;2. Department of Biochemistry and Molecular Biology, Faculty of Science, University of Rajshahi, Rajshahi‐6205, Bangladesh |
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Abstract: | The present study is the first report describing the purification, enzymatic properties and N‐terminal amino acid sequence of a native invertase in betel leaf. The invertase was purified as a monomeric glycoprotein of molecular mass (Mr) 68 kDa. The enzyme was capable to attack β‐fructofuranoside linkages from the fructose end of sucrose, raffinose and stachyose indicating it as an authentic β‐D‐fructofuranosidase with high specificity for sucrose (Km 4.83 mM). The maximum activity was detected at pH 5.2 and 37 °C. Glucose and fructose showed typical inhibitory effect on the enzyme activity where as lectin was found to be effective activators of the enzyme. Significant inhibition by heavy metal ion Hg2+ and sulfhydryl group modifying agents suggesting that free sulfhydryl group containing amino acid, cysteine is necessary for the catalytic activity of the invertase. A BLAST search of the N‐terminal amino acid sequence of betel leaf invertase showed significant homology with the homologous invertases in database. |
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Keywords: | Betel leaf β ‐D‐fructofuranosidase Invertase N‐terminal sequence Sucrose |
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