Transport of CMP-N-glycoloylneuraminic acid into mouse liver Golgi vesicles |
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Authors: | A Lepers L Shaw R Cacan R Schauer J Montreuil A Verbert |
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Affiliation: | Laboratoire de Chimie Biologique, Université des Sciences et Techniques de Lille, Villeneuve d'Ascq, France. |
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Abstract: | CMP-Neu5Gc has been shown to be transported into mouse liver Golgi vesicles by a specific carrier the characteristics of which were investigated in detail. In the system employed, CMP-Neu5Gc enters the Golgi vesicles within 2 min; transport was saturable with high concentrations of the sugar-nucleotide and was dependent on temperature. A kinetic analysis gave an apparent Km of 1.3 μM and a maximal transport velocity of 335 pmol/mg protein per min. Almost identical values were obtained with CMP-Neu5Ac, under the same incubation conditions. Furthermore, the uptake of CMP-Neu5Gc was inhibited by CMP-Neu5Ac, a substrate analogue. Conversely, the uptake of CMP-Neu5Ac was inhibited by CMP-Neu5Gc to the same extent, leading to the conclusion that the transport of CMP-Neu5Ac and CMP-Neu5Gc is mediated by the same carrier molecule. This transport system for CMP-Neu5Gc involves both CMP and CMP-Neu5Gc since intravesicular CMP induced the entry of external CMP-Neu5Gc. |
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Keywords: | Transport CMP-sialic acid Golgi vesicle |
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