Transfer of N-acetylglucosamine to endogenous glycoproteins in the nucleus and in non-nuclear membranes of rat hepatocytes: electrophoretic analysis of the endogenous acceptors |
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Authors: | S Galland A Degiuli J Frot-Coutaz R Got |
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Affiliation: | Laboratoire de Biochimie des Membranes, LBTM CNRS UM 380024, Université Claude Bernard, Lyon 1, Villeurbanne, France. |
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Abstract: | The transfer of N-acetyl(14C)glucosamine from UDP-N-acetyl(14C)glucosamine to endogenous glycoproteins acceptors were studied comparatively in the nuclei and in the non-nuclear membranes of rat hepatocytes. Electrophoretic and autoradiographic analysis show that most of the glycoprotein acceptors of the nuclei differ from those of the non-nuclear membranes in terms of molecular weight. In addition, it may interesting to mention that in the nuclear fraction a 30% inhibition by tunicamycin is obtained for concentrations as low as 0.03 microM, whereas at this concentration no effect is detected in the non-nuclear membranes. In the presence of 0.2 microM tunicamycin, the inhibition does not go beyond 25% in the latter fraction but goes up to 80% in the former. The previous results demonstrate clearly that a particular glycosylation reaction occurs in the nucleus. |
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