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PURIFICATION AND CHARACTERIZATION OF ESCULENTAMIN, A PROTEINACEOUS ALPHA‐AMYLASE INHIBITOR FROM THE TARO ROOT, COLOCASIA ESCULENTA
Author(s) -
SELTZER ROBERT D.,
STRUMEYER DAVID H.
Publication year - 1990
Publication title -
journal of food biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.507
H-Index - 47
eISSN - 1745-4514
pISSN - 0145-8884
DOI - 10.1111/j.1745-4514.1990.tb00834.x
Subject(s) - chemistry , ammonium sulfate precipitation , biochemistry , colocasia esculenta , sephadex , chromatography , urea , trypsin , size exclusion chromatography , trypsin inhibitor , proteases , enzyme , biology , botany
A proteinaceous alpha‐amylase inhibitor from the cormel of taro (Colocasia esculenta) was purified by extraction, heat treatment, ammonium sulfate precipitation, and column chromatography on Sephadex G‐100, BioGel P‐30, and DE‐53 cellulose . This protein (aptly named esculentamin) was shown to be an acidic (pI = 4.4) glycoprotein with a carbohydrate content of 3.64% and a molecular weight of 11,800 daltons. Esculentamin activity was essentially stable to boiling for 3 h (pH 7.0), to a pH range of 2.0 to 12.0 (at 4°C), and to 6 M guanidine hydrochloride and 8 M Urea. Amino acid analysis indicated a predominance of acidic over basic amino acids, while side‐by‐side neutral and alkaline absorption spectra strongly suggested a lack of tryptophan . “Bifunctional” inhibitory activity towards both α‐amylase and proteases was not observed with esculentamin (i. e., it did not inhibit the several proteases tested, viz. trypsin and subtilisin) .