Monosaccharides physical methods

The conformational analysis of monosaccharides, disaccharides, and ohgosaccharides is reviewed. Conformational terms are introduced through examination of the conformations of cyclohexane and cyclopentane then applied to the pyranose, furanose, and septanose rings. Concepts such as the anomeric effect are discussed. Topics of current interest, such as hydroxymethyl group and hydroxyl group rotation and disaccharide conformations are summarized. Physical methods for studying conformation are outlined. 

In this article, the authors have endeavored to summarize the methods of synthesis and the proofs of constitution of all the known methyl ethers of D-glucopyranose and D-glucofuranose. Acyclic glucose ethers are not considered in this review. Later articles will deal with monosaccharides other than glucose. It has not been possible to discuss in full all the reactions involved, but to offset this disadvantage the bibliography has been made as complete as possible and tables have been compiled of the physical properties of the methyl-D-glucoses and of their more important derivatives. 

In addition to determining the monosaccharide composition, linkage types, and sequence of residues in a cell wall polysaccharide, it is also essential to determine the anomeric configuration of the glycosyl residues. As with determining the sequence of glycosyl residues, the method of choice, be it chemical, enzymic, or physical, are dependent on the type of material under investigation and the amount available. 

N-acetyl glucosamine is also an inhibitor of lysozyme, but in contrast to the oligosaccharide inhibitors, its action is due to binding across, rather than in, the cleft of the active site (24). Monosaccharides are known to inhibit some 0-glucan endo-hydrolases (202) and a physical explanation of this kind is possible, but would be difficult to confirm without recourse to crystallographic methods. 

C A Browne and F W Zerban, Physical and Chemical Methods of Sugar Analysts, 3rd edition, John Wiley and Sons, New York, 1941, J Stanek, M Carny, J Kocourek and J Pacak, The Monosaccharides, Academic Press, New York, 1963, pp 865 955, G R Pigman in The Carbohydrates, (Ed W Pigman), Academic Press, New York, 1957, pp 602 640... 

Recently, much attention has been given to the production of liquid sweeteners as an alternative to cane sugar using inexpensive starch-containing natural materials as the primary feed stock. This situation exists in the United States as this country is not self sufficient in the production of cane, but must rely heavily on importation mainly from South America and the Caribbean. The main source of sta rch in the United States comes from corn (Zea mays) and the liquid sweetener commercially produced from this material is called high fructose corn syrup (HFCS). The current method of production of HFCS is via wet milling which exploits the physical properties of the whole corn constituents (oil, starch, gluten, and fiber) for their separation coupled with enzymatic hydrolysis of the starch fraction to monosaccharides. 

There is a great variety in structure as well as chemical and physical properties of monosaccharides. There is no single method that is applicable to the qualitative and quantitative analysis of all monosaccharides instead, the method must be chosen according to the chemical and physical characteristics of the solutes of interest. Borate complexes of monosaccharides can be separated using strong (quaternary amine, Q-type) anion-exchange columns. Alternatively, if the monosaccharide is acidic... 

About the same time, a new international research journal, Carbohydrate Research, appeared (volume 1) in 1964. It has become the principal journal for the publication of all aspects of carbohydrate research, such as chemical synthesis and modification enzymatic synthesis organic and enzymatic mechanisms involving carbohydrates carbohydrate metabolism conformational analysis isolation of carbohydrates from natural sources analytical methods chemistry of monosaccharides, oligosaccharides, and polysaccharides biological function of carbohydrates and physical properties. Approximately four to five volumes are published each year. 

---