Incorporation of fucose

Different glycolipid fucosyltransferase activities have been reported (32,55,58) to catalyze the addition of fucose to position C-2 of the terminal D-galactose and position C-3 of the internal N-acetylglucosamine of nLcOse4Cer to form blood group H or human tumor-specific lipid (10). Incorporation of fucose into GgOse4Cer was also reported recently by Taki et al. 

Trujillo and Gan (1971) have studied the incorporation of fucose-1-by bovine thyroid slices. Only 0.15% of the label was oxidized to carbon dioxide, whereas appreciable labeling of both acid-soluble and acid-insoluble materials was observed. Radioactivity was incorporated into glycoprotein without detectable labeling of sugars other than fucose. Thus fucose-l- G appears to be an excellent precursor for studying glycoprotein synthesis by thyroid, as is the case for liver (Section IV,A,3). 

The 6-fluoro derivatives of Gal and Fuc do not decrease the pools of ribonucleotides, nor do they inhibit protein synthesis.234,304 Interestingly, when present in low concentrations, most fluoro sugars do not give cytotoxic effects.304,313 When the size of the halogen atom is increased (Cl — Br — I derivatives), incorporation of L-fucose is lessened, and, for as-yet-unknown reasons, a concomitant increase in cytotoxicity was noted.304... 

Little research has as yet been published on the biochemistry of incorporation of L-fucose into bacterial glycans. Most of the studies have been made on the genetics of the biosynthesis of colanic acid in Gram-... 

When cells were cultured in labelled fucose or galactose in the presence or absence of butyrate, alterations in the labelled glycolipids were observed. Treatment of all of the cell lines with butyrate did not markedly affect the incorporation of l hJ galactose in ganglioside per milligram of cell protein. 

Values not given in parentheses represent incorporation of [14C]fucose into respective substrates using high specific activity GDP-[14C]fucose (189 mCi/mmole ... 

Additional evidence for an alternative pathway for the production of L-fucose came from experiments in mouse lymphoma cell lines blocked in the conversion of GDP-D-[ H]-mannose to GDP-L-[ H]-fucose. Reitman et al. observed that the block could be bypassed by growing the cells in the presence of L-fucose [119]. That this short activation pathway may be a general salvage mechanism is also indicated by the fact that 6-deoxy-D-glucose derivatives could be incorporated into neomycin [71]. The existence of a short activation pathway was recently proven in our laboratories [120] by successful incorporation of l-[2, 3--H2]-rhodinose [121] into landomycin A (12). In this experiment, NMR spectroscopy of the product showed, that only the four protons of the two L-rhodinose moieties were labeled. In a control experiment, d-[2, 2, 3, 3- H4]-rhodinose [121] was fed and, as expected, no incorporation into 12 was observed [120] (Scheme 27). 

Nucleotide sugars, such as UDP-glucose, serve as donors during the incorporation of sugar residues into gangliosides. In this case, it appears that the donor of fucose residues is GDP-fucose, which is synthesized from fucose and GTP... 

Localization of glycoproteins in lysosomes and prelysosomes of a kidney epithelial cell line from monkey has been established by use of high resolution autoradiography after incorporation of L-[ H]fucose and by a semicarbazide-... 

Colchicine, given intraperitoneally to rats before and after injection of L-[ H]fucose, markedly inhibits the incorporation of labelled glycoprotein into microvillus membrane with a corresponding increase in incorporation into the lateral basal membrane. By using specific immunochemical techniques in combination with two-dimensional electrophoresis, it is possible to identify a set of four glycoprotein sub-units present only in placental brush border membranes. A group of seven placental glycoproteins was found to be common to liver and kidney membranes. 

Hormonal effects on the biosynthesis of sulphated glycoprotein in the endometrium of rabbit uterus have been shown to be confined to the microsomal level. Oestrogen increases the incorporation of L-fucose and 2-acetamido-2-deoxy-D-glucose from their respective nucleotides into a microsomal fraction, while progesterone suppresses the incorporation of the two sugars. 

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