Lyxose 5-deoxy-3-formyl

L-Streptose 5-deoxy-3-formyl-L-lyxose, a monosaccharide, 162.14, with a branehed carbon chain. In combination with 2-deoxy-2-methyIamino-L-glucose, L-S forms streptobiosamine, the disaccharide component of Streptomycin (see). l-S. is biosynthesized by rearrangement of an unbranched hexose. 

Streptobiose 2-Deoxy-2-methylamino-a-L-glucopyranosyl-(1 2)-5-deoxy-3-C-formyl-L-lyxose 

The earliest known member of this group was streptose, which is present in streptomycin. Its structure was shown to be that of 5-deoxy-3-C-formyl-L-lyxose (57). Both a hydroxylated and a reduced form of streptose have been found in variants of streptomycin produced by other Streptomyces sp. The former, 5-hydroxystreptose (3-formyl-L-lyxose) (58), occurs in hydroxystreptomycin and the latter, dihydrostreptose Q5-deoxy-3-(hydroxymethyl)-L-lyxose] (59), in dihydrostreptomycin. 

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