11.8: The Eight Essential Monosaccharides
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- Steven Farmer & Dietmar Kennepohl
- Cañada College
Objectives
1. identify and draw the eight essential monosaccharides
Eight monosaccharides are required for the proper functioning of human beings. Although they are typically supplied through a healthy diet, they can be biosynthesized if required. The eight monosaccharides are
D-Galactose, D-Glucose, and D-Mannose are commonly found aldohexoses:
D-Xylose is a common aldopentose.
D-Xylose
L-Fucose is a deoxy sugar. Fucose is is the monosaccaride L-galactose with the -OH group on C6 replaced with an -H.
N-acetylgalactosamine and N-acetylglucosamine are derivatives where the corresponding amino sugars have been converted to amides by N-acylation. Amino sugars have had their -OH groups at C2 replaced by an -NH 2 .
N-Acetylneuraminic acid is nine carbon sugar created by an aldol reaction between N-acetymannosamine and pyruvate. N-acetylneuaminic acid forms a pyranose ring by a intramolecular hemiacetal formation between the -OH on C6 and the ketone functional group in the pyruvate moiety.
Exercise \(\PageIndex{1}\)
1) Please show the mechanism of the aldol reaction between
N
-acetylmannosamine and pyruvate
- Answer
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1)