| Autor: |
E C, Brinkman-Van der Linden, R, Mollicone, R, Oriol, G, Larson, D H, Van den Eijnden, W, Van Dijk |
| Rok vydání: |
1996 |
| Předmět: |
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| Zdroj: |
The Journal of biological chemistry. 271(24) |
| ISSN: |
0021-9258 |
| Popis: |
The major alpha3-fucosyltransferase activity in human plasma is encoded by the gene for fucosyltransferase VI (FUT6). A missense mutation (Gly-739 --Ala) in this gene is responsible for deficiency of enzyme activity in plasma. To examine whether this fucosyltransferase is the sole enzyme responsible for the alpha3-fucosylation of serum glycoproteins in the liver, we studied the fucosylation of three glycoproteins in sera of individuals with or without inactivated FUT3 and/or FUT6 gene(s) but with a functional FUT5 gene. alpha1-Acid glycoprotein was used as the principal reporter protein for liver alpha3-fucosyltransferase activity, because of its high fucose content. In all individuals with the FUT6 missense mutation Gly-739 --Ala in double dose, no fucosylation of alpha1-acid glycoprotein was found. This alpha1-acid glycoprotein was not intrinsically resistant to fucosylation, since it was susceptible to in vitro fucosylation using an alpha3/4-fucosyltransferase isolated from human milk. The same result was found for alpha1-antichymotrypsin and alpha1-protease inhibitor. On the other hand in all individuals with alpha3-fucosyltransferase activity in plasma, alpha3-fucosylated glycoforms of the glycoproteins studied were found. The degree of fucosylation of alpha1-acid glycoprotein was correlated with alpha3-fucosyltransferase activity (Rs = 0.82). These data indicate that the product of FUT6, but not of FUT3 or of FUT5, is responsible for the alpha3-fucosylation of glycoproteins produced in liver and suggest that this organ is a major source of alpha3-fucosyltransferase activity in plasma. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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