General Properties, Occurrence, and Preparation
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87
and is found in relatively large amounts in pears, apples, cherries, prunes, peaches, and apricots, where it imparts a sweet taste to these fruits [125].
D-Mannitol is also widely distributed in plants and was the first crystalline sugar alcohol to
be obtained from a natural source, the manna ash [126]. It is also found in large amounts
(70–90% w/w) in the exudates of the olive and the plane trees [127]. D-Mannitol is found
in relatively large amounts in seaweeds of Laminaria and Mycrocystis species [128]. Species
of the mold Aspergillus, produce D-mannitol by fermentation, using D-glucose or acetate as
carbon sources [129].
Ribitol, the sugar alcohol from the reduction of D-ribose, is found as a constituent of the
vitamin riboflavin (vitamin B 2 ). It is also a constituent of the teichoic acids, see > Sect. 12.3.
The reduced product of D-xylose is xylitol, which has a very sweet taste and also imparts
an unusual cooling sensation. It is found in several fruits, such as plums, raspberries, and
strawberries, where it occurs to the extent of about 1% by weight and gives a distinctive and
pleasant taste to these fruits. D-Arabinitol is found in mushrooms in amounts as high as 9–
10% by weight [130], in lichens [131], and in avocado seeds [132]. D-Arabinitol is produced
by some species of yeast (Debaryomyces subglobosus and Endomycopsis chodati) through
fermentation of D-glucose, D-mannose, and sucrose [133].
12.3 Sugar Alcohols in Teichoic Acids
The teichoic acids are bacterial polymers of sugar alcohols (glycerol or ribitol) and phosphoric acid joined end to end by phosphodiester linkages to the primary alcohol groups. They are
found in conjunction with the peptidoglycan of Gram-positive bacterial cell walls [134]. The
C2 hydroxy group of glycerol is frequently acylated by D-alanine or glycosylated by N-acetylD-glucosamine or D-glucopyranose [135]. In some Bacillus species phosphodiester linkages
join glycerol units between the C1 hydroxy of one unit to the C2 hydroxy of the next unit.
Ribitol residues are joined together between the C1 hydroxyl of one unit to the C5 hydroxy
of the adjoining unit. The C3 or C4 hydroxy groups can be acylated by D-alanine and the C2
hydroxyl group can be glycosylated by a number of different carbohydrate residues, for example, N-acetyl-D-glucosamine, D-glucopyranose, and di- or tri-saccharides of D-glucopyranose.
More complex teichoic acids occur that have a repeating sequence of glycerol joined (1→4)
to N-acetyl-D-glucosamine by a phosphodiester linkage and N-acetyl-D-glucosamine joined
(1→3) by a phosphodiester linkage to the next glycerol unit [136].
13 Properties and Occurrence of Deoxy Sugars
The most abundant and probably best known deoxy sugar is 2-deoxy-D-ribofuranose, which
is found as the carbohydrate component in the genetic polymer, deoxyribonucleic acid,
the carrier of genes in the chromosomes of living organisms. Other deoxy sugars include
6-deoxy-L-mannose (L-rhamnose), which is found in glycosides and in Salmonella sp.
O-antigen polysaccharides (see > Sect. 10.2). The third deoxy sugar is 6-deoxy-L-galactose
(L-fucose), found in glycocoproteins, such as the blood group substances (see > Sect. 14).
The fourth deoxy sugar, 6-deoxy-D-glucose (D-quinovose) is found in acarbose, the naturally occurring pseudotetrasaccharide, produced by Actinoplanes sp. fermentation. Acarbose
is an inhibitor of α-glucosidase [137]. It also occurs in some of its analogues, such as
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87
and is found in relatively large amounts in pears, apples, cherries, prunes, peaches, and apricots, where it imparts a sweet taste to these fruits [125].
D-Mannitol is also widely distributed in plants and was the first crystalline sugar alcohol to
be obtained from a natural source, the manna ash [126]. It is also found in large amounts
(70–90% w/w) in the exudates of the olive and the plane trees [127]. D-Mannitol is found
in relatively large amounts in seaweeds of Laminaria and Mycrocystis species [128]. Species
of the mold Aspergillus, produce D-mannitol by fermentation, using D-glucose or acetate as
carbon sources [129].
Ribitol, the sugar alcohol from the reduction of D-ribose, is found as a constituent of the
vitamin riboflavin (vitamin B 2 ). It is also a constituent of the teichoic acids, see > Sect. 12.3.
The reduced product of D-xylose is xylitol, which has a very sweet taste and also imparts
an unusual cooling sensation. It is found in several fruits, such as plums, raspberries, and
strawberries, where it occurs to the extent of about 1% by weight and gives a distinctive and
pleasant taste to these fruits. D-Arabinitol is found in mushrooms in amounts as high as 9–
10% by weight [130], in lichens [131], and in avocado seeds [132]. D-Arabinitol is produced
by some species of yeast (Debaryomyces subglobosus and Endomycopsis chodati) through
fermentation of D-glucose, D-mannose, and sucrose [133].
12.3 Sugar Alcohols in Teichoic Acids
The teichoic acids are bacterial polymers of sugar alcohols (glycerol or ribitol) and phosphoric acid joined end to end by phosphodiester linkages to the primary alcohol groups. They are
found in conjunction with the peptidoglycan of Gram-positive bacterial cell walls [134]. The
C2 hydroxy group of glycerol is frequently acylated by D-alanine or glycosylated by N-acetylD-glucosamine or D-glucopyranose [135]. In some Bacillus species phosphodiester linkages
join glycerol units between the C1 hydroxy of one unit to the C2 hydroxy of the next unit.
Ribitol residues are joined together between the C1 hydroxyl of one unit to the C5 hydroxy
of the adjoining unit. The C3 or C4 hydroxy groups can be acylated by D-alanine and the C2
hydroxyl group can be glycosylated by a number of different carbohydrate residues, for example, N-acetyl-D-glucosamine, D-glucopyranose, and di- or tri-saccharides of D-glucopyranose.
More complex teichoic acids occur that have a repeating sequence of glycerol joined (1→4)
to N-acetyl-D-glucosamine by a phosphodiester linkage and N-acetyl-D-glucosamine joined
(1→3) by a phosphodiester linkage to the next glycerol unit [136].
13 Properties and Occurrence of Deoxy Sugars
The most abundant and probably best known deoxy sugar is 2-deoxy-D-ribofuranose, which
is found as the carbohydrate component in the genetic polymer, deoxyribonucleic acid,
the carrier of genes in the chromosomes of living organisms. Other deoxy sugars include
6-deoxy-L-mannose (L-rhamnose), which is found in glycosides and in Salmonella sp.
O-antigen polysaccharides (see > Sect. 10.2). The third deoxy sugar is 6-deoxy-L-galactose
(L-fucose), found in glycocoproteins, such as the blood group substances (see > Sect. 14).
The fourth deoxy sugar, 6-deoxy-D-glucose (D-quinovose) is found in acarbose, the naturally occurring pseudotetrasaccharide, produced by Actinoplanes sp. fermentation. Acarbose
is an inhibitor of α-glucosidase [137]. It also occurs in some of its analogues, such as