Sugar transfer, specificity

The native Pasteurella and the recombinant Escherichia co//-derived preparations of the various microbial Pasteurella GAG synthases rapidly form long polymer chains in vitro (2). The sugar transfer specificity of the native-sequence enzymes is exquisite and only the authentic sugars are incorporated into polymer products. For example, the native synthase enzymes do not utilize significantly the C4 epimer precursors in comparison to the natural UDP-sugars. 

However, as described later, the sugar acceptor specificity is not as precise as the sugar transfer specificity allowing one synthase to extend non-cognate GAG polymers to create chimeric polysaccharides. 

Fucose, galactose, and sialic acid residues are added in the trans-Golgi and trans-Golgi network compartments. The membranes of the Golgi compartments contain nucleotide-sugar translocases specific for transferring each nucleotide sugar across the membrane. 

This enzyme catalyzes the phosphoryl transfer from MgATP to glucose or analogous sugars. Of specific interest in the study of the reaction mechanism of... 

Each enzyme is specific for the sugar transferred, its nucleotide precursor, the residue to which it is transferred and the bond formed. All are effectively irreversible transfers and all the enzymes are membrane-bound. The rhamnosyl and mannosyl transferases can be solubilised with non-ionic... 

Figure 7. Analysis of various chimeric synthases. Portions of the pmHAS (black) and pmCS (white) enzymes were fused to produce chimeric enzymes. The constructs were tested for sugar transfer activity (HAS, HA synthase CS, chondroitin synthase GlcUA transferase) in vitro. The last enzyme, pmCHC, had relaxed specificity and could incorporate either UDP-hexosamine.

The SUGAR style-specific microprocessor designer includes both behavioral transformation and Register-Transfer Level synthesis functions. 

Specific sugar consumption rate = 1.0kg-kg 1 cell h 1 The mass transfer coefficient is calculated by the following correlation... 

Nielsen KK, Nielsen JE, Madrid S, Mikkelsen JD. New antifungal proteins from sugar beet Beta vulgaris L.) showing homology to non-specific lipid transfer proteins. Plant Mol Biol 1996 31 539-552. 

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