Biosynthesis glucosamine formation

Not much has been added to the biochemistry of STRs in the recent years. Therefore, we will only briefly treat the biosynthetic pathway here. Biosynthesis of the aminocyclitol (streptidine) and 6-deoxyhexose (streptose) moieties are well understood, with some remaining gaps in the enzymology. Much less is known about the residual biosynthetic phases, the formation of A-methyl-L-glucosamine, the condensation of subunits, and the late modification steps potentially coupled with export. ... 

The mechanism of cyclopentane ring formation of allosamizoline may take place via pathway A or B during inositol biosynthesis, whereas via pathway C during shikimic acid biosynthesis (Scheme 1). This was based on a study using [3- H]-, [4- H]-, [5- H]-and [6- H2]-D-glucosamine feeding in experiments which indicated that the cyclization to form the cyclopentanoid moiety of allosamizoline is presumed to proceed via a 4-keto or... 

The biosynthesis of the N-methyl-L-glucosamine moiety of streptomycin from D-glucosamine by S.griseus has been studied. Addition of thymine to the culture medium stimulated formation of streptomycin, and the conversion of D-glucosamine to N-methyl-L-glucosamine. A novel UDP-aminosugar nucleotide intermediate,... 

The biosynthetic pathway for sialic acid formation in liver was well established nearly thirty years ago, by the elegant work from the groups of Roseman [9-11] and Warren [12] (Figure 1). The enzymatic conversion of UDP-A-acetyl glucosamine to A-acetylmannosamine is the critical step in the overall synthesis of sialic acid because the activity of this epimerase is controlled downstream in the pathway by feedback inhibition by CMP-A -acetylneuraminic acid [13]. Thus, production of ManNAc as a precursor for sialic acid biosynthesis is a closely regulated cellular process. 

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