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Título
Characterization, Hydrolytic Activity and Variations throughout Growth of a Cell Wall β-Glucosidase and a-Galactosidase from Cicer arietinum epicotyls
Autor(es)
Materia
Cicer arietinum L.
Cell wall alpha-galactosidase
Cell wall beta-glucosidase
Growth
Hydrolysis
Fecha de publicación
1991
Resumen
In the cell walls of epicotyls of Cicer arietinum we found beta-glucosidase and a-galactosidase activities, the former being predominant. We purified and characterized these enzymatic activities. The beta-glucosidase activity is found associated with a protein fraction that also shows beta-galactosidase and beta-xylosidase activity. lt is formed by two subunits of approximately 60-65 kDa, with elevated activity between pH 6 and 8 and an optima! temperature of 70 ºC, inhibited by Hg2+ . The values of Km and Vmax vary for each of its principal activities, being 2.2 mM and 378.6 nkat (mg protein)- 1, respectively, for beta-glucosidase activity. The fraction with the a-galactosidase activity is also formed by subunits of molecular weight of 35-45 kDa. lt shows an optimum pH of 5 and 40 ºC, its Km and V max being 0.27 mM and 32.8 nkat (mg protein)- 1. lt is inhibited by Hg2+ and galactose. Throughout growth of the epicotyls, beta-glucosidase activity increased and a-galactosidase showed an activity profile with a maximum to the 5th day. These enzymes were not able to hydrolyze the non-cellulosic fractions of the cell wall. lts physiological role remains unknown.
URI
ISSN
0176-1617
DOI
10.1016/S0176-1617(11)80320-2
Colecciones
- GIPACYCV. Artículos [58]
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b-glc y a-gal caracterizacion_J Plant Physiol 1991.pdfEmbargado hasta: 2099-09-09
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Artículo de investigación