A3-fucosyltransferase

Natunen, J., O. Aitio, J. Helin et al. 2001. Human a3-fucosyltransferases convert chitin oligosaccharides to products containing a GlcNAcl31-4(Fucal-3)GlcNAc61-4R determinant at the nonreducing terminus. Glycobiology 11 209-216. 

Figure 3. Substrate specificities of the various vertebrate a3/4-fucosyltiansferases. This graph shows the capacity of each a3-fucosyltransferase isoform to catalyze the synthesis of the various Lewis determinants.

The FucT V and VI, are found in the plasma, and they catalyze the formation of Fucal,3GlcNAc linkages and produce Le and sLe structures. High expression levels of these enzymes have also been identified in neoplastic tissues, especially in cancers of the lung [41]. The levels of a3-fucosyltransferase activity in plasma are also increased in chronic liver diseases, such as hepatitis, cirrhosis and hepatocellular carcinoma. Indeed, quantitation of this fucosyltransferase activity in plasma can be used as indicator of these diseases [42]. 

GDP-Fucose Galpl,3GlcNAc(Fucal,3GlcNAc) bacterial Helicobacter pylori) a3 fucosyltransferase... 

C.H. Hokke, A.P. Neeleman, C.A.M. Koeleman and D.H. Van den Eijnden, Identification of an a3-fucosyltransferase and a novel a2-fucosyltransferase activity in cercariae of the schistosome Trichobilharzia ocellata—Biosynthesis of the Fucal- 2Fucal 3[Gal(NAc)pi—>4]GlcNAc sequence. Glycobiology, 1998, 8, 393-406. 

Another specific modification of polylactosaminoglycan chains is the introduction of a3-Fuc residues to non-terminal GlcNAcs along the chain to yield a (sialyl-) oligomeric-Lewis structure. In leukocytes the formation of this structure, which is a ligand for E- and P-selectin, is catalyzed by two different a3-FucTs, the myeloid FucT (FucT IV) and the leukocyte FucT (FucT VII) [92, 93] (Figure 10) (see also Section 23.20, o314-Fucosyltransferase Family below). 

Within the a3/4-fucosyltransferase family six different members have been identified. They are numbered in the order they were cloned FucT III-VII and IX. Human FucT III (Lewis enzyme), V and VI (hver/plasma enzyme) are highly related enzymes with >90% identity at the amino acid level in their catalytic domain their genes are all located on human chromosome 19 [135]. By contrast, FucT IV (myeloid enzyme, chromosome 11) and FucT VII (leukocyte enzyme, chromosome 9) have a more distal relationship to each other and to the other members of this family [135, 136]. Recently a novel member, FucT IX, which has highest homology to FucT rv, was cloned from a mouse library [137]. Recently the human ortholog of FucT IX was described [138]. 

The original nomenclature for the various isoforms of fucosyltransferases, based upon the order in which the genes were isolated, was established by Pamela Stanley [1] and further extended by John Lowe. FucT I and II were used to designate fucosyltransferases activities found in the lectin-resistant CHO cell lines LECH and LEC12 the next five fucosyltransferases identified were human a3,4-fucosyl-transferases whose genes have been cloned (FucT III to VII) [2-8]. 

GDP-Fucose Gaipi,4/3GlcNAc(Fucal,3/4GlcNAc)a3/4-fucosyltransferases... 

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