Biosynthesis 6-deoxy-hexoses

Subsequent Reactions Catalyzing 6-Deoxyhexose Formation 3,5-Epimerase and Reductase. After the formation of the 4-keto intermediate, a step common to all deoxyhexose formations, at least two and possibly three additional enzymes are necessary for the biosynthesis of the end product. This sequence of transformations is illustrated in Figure 3. The first step is the conversion of the 4-keto-6-deoxy-hexose intermediate described above. The intermediates in brackets are postulated and are assumed to be bound to the enzyme. An enzyme (or enzymes), referred to below as 3,5-isomerase, catalyzes epimerizations at carbons 3 and 5, probably via the enediol form. The epimerizations are followed by a... 

The chemoenzymatic synthesis of dTDP-p-L-olivose and dTDP-a-L-olivose, donor substrates for the biosynthesis of polyketides and other drugs, has been described. Starting from 2-deoxy-D- ra/u o-hexose 6-phosphate, dTDP D-oliose was also synthesized.174... 

Kneidinger, B., Larocque, S., Brisson, J.-R., Cadotte, N., Lam, J.S. Biosynthesis of 2-acetamido-2,6-dideoxy-L-hexoses in bacteria follows a pattern distinct from those of the pathways of 6-deoxy-L-hexoses. Biochem J 371 (2003) 989-995. 

U. F., Salah-Bey, K., Benhamou, B., Capdevila, C., Michel, ).M., Piepersberg, W. Raynal, M.C. Analysis of genes involved in 6-deoxy-hexose biosynthesis and transfer in Saccharo-polysporaerythraea. Mol. Gen. Genet. 264, 477-485 (2000). 

Progress has also been made on the biosynthesis of nucleotide-bound 3,6-dideoxyhexoses. Thus, GDP-colitose (-3,6-dideoxy-L-xt//o-hexose) was shown to be enzymically synthesized from GDP-D-man-nose by way of GDP-6-deoxy-D-li/xo-hexos-4-ulose CDP-paratose, CDP-adequose (-3,6-dideoxy-D-xi/lo-hexose), CDP-tyvelose, and CDP- ascarylose (-3,6-dideoxy-L-arafefno-hexose) from CDP-D-glu-... 

Pyranoid sugar conjugates having an exocyclic, enolacetal double bond were postulated as intermediates in the biosynthesis of 6-deoxy-L-hexoses (for example in strains of Escherichia coli)Pyranoid derivative 229, bearing an exocyclic, enolacetal linkage, is formed from 228, and is transformed by way of 229 into the isomeric compound (230) having the enolacetal double bond in the endocyclic position. 

Inhibition by 2-deoxy-D-arai>mn-hexose of the biosynthesis of the cell-wall mannan in Saccharomyces cerevisiae appears to involve a complex mechanism that disrupts the synthesis of protein rather than glycosylation. Studies using a particulate enzyme from Mycobacterium smegmatis have demonstrated that polyisoprenyl D-mannosyl phosphates are obligatory donors, while preparations obtained from Hansenula holstii have shown that a D-mannosyl-lipid is involved in the synthesis of mannosylated serine (or threonine) residues. ... 

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