Chitin synthetase activity is bound to the plasma membrane and to a cytoplasmic particulate fraction in Candida albicans germ tube cells |
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Authors: | Daniel Gozalbo Francisco Dubón Rafael Sentandreu |
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Institution: | Unitat de Microbiología, Facultat de Farmàcia, Universitat de València, València, Spain |
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Abstract: | Abstract Subcellular distribution of chitin synthetase has been studied in germ tubes of Candida albicans . Two fractions with synthetase activity were separated from cell homogenates: (i) a mixed membrane fraction where the enzyme, partly in an active form, is associated with the plasma membrane (isopycnic centrifugation of mixed membrane fraction on linear sucrose gradients resolved a unique peak of activity matching with 3H]ConA-labelled membranes at a buoyant density of 1.195 g/ml); and (ii) a cytoplasmic fraction containing fully zymogenic enzyme associated with particles whose buoyant density (determined by isopycnic centrifugation on linear sucrose gradients) depended on the cell breakage conditions. The actual cytoplasmic fraction-enzyme may correspond to particles with buoyant density 1.135 g/ml (chitosomes), whereas the enzyme particles with other densities (1.085 and 1.165 g/ml) probably originated during cell disruption, as has been reported previously to occur during the preparation of yeast cell homogenates. |
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Keywords: | Candida albicans Germ tube formation Chitin synthetase Dimorphism Subcellular fractionation |
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