Biological processes, carbohydrates

Up to this point all our attention has been directed toward aldoses carbohydrates hav ing an aldehyde function in their open chain form Aldoses are more common than ketoses and their role m biological processes has been more thoroughly studied Nev ertheless a large number of ketoses are known and several of them are pivotal inter mediates m carbohydrate biosynthesis and metabolism Examples of some ketoses include d nbulose l xylulose and d fructose... 

Lectins are carbohydrate-binding proteins involved in cell adhesion and other biologic processes. 

L. L. Kiessling, J. K. Pontrello, and M. C. Schuster, Synthetic multivalent carbohydrate ligands as effectors or inhibitors of biological processes, in C.-H. Wong, (Ed.), Carbohydrate-Based Drug Discovery, Wiley-VCH Weinheim, Germany, 2003, pp. 575-608. 

Carbohydrate conformation plays a key role for molecular recognition processes, and their determination contributes to the understanding of many biological processes. The latest NMR methodological developments for conformation determination are discussed here, and representative examples are given. 

It is clear that protein-carbohydrate interactions are essential in numerous biological processes and that the development of carbohydrate mimetics that interfere with these processes would provide a powerful methodology for both modulation and amelioration of specific biological activity. Since the early 1990s, novel... 

First, the above-mentioned sensors have major drawbacks, as the detection and recognition event is a function of the nature and characteristics of the side chains, and the side chain functionalization of the CP requires advanced synthesis and extensive purification of numerous monomeric and polymeric derivatives. Second, this generation of sensors primarily employed optical absorption as the source for detection, resulting in lower sensitivity when compared with other sensing systems for biological processes. However, the use of fluorescence detection within these sensing systems could justify continued development. More recent examples include a fluorescent polythiophene derivative with carbohydrate functionalized side chains for the detection of different bacteria [15] and novel synthesis schemes for ligand-functionalization of polythiophenes [16]. 

The carbon cycle, one of the most essential of all biological processes, involves the chemical conversion of carbon dioxide to carbohydrates in green plants by photosynthesis. Animals consume the carbohydrates and, through the metabolic process, reconvert the carbohydrates back into carbon dioxide, which is returned to the atmosphere to continue the cycle. 

Nucleic acids, proteins, some carbohydrates, and hormones are informational molecules. They carry directions for the control of biological processes. With the exception of hormones, these are macromolecules. In all these interactions, secondary forces such as hydrogen bonding and van der Waals forces, ionic bonds, and hydrophobic or hydrophilic characteristics play critical roles. Molecular recognition is the term used to describe the ability of molecules to recognize and interact bond—specifically with other molecules. This molecular recognition is based on a combination of the interactions just cited and on structure. 

Reuter, G. Gabius, H.-J. (1999) Eukaryotic glycosylation whim of nature or multipurpose tool Cell. Mol. Life Sci. 55, 368-422. Excellent review of the chemical diversity of oligosaccharides and polysaccharides and of biological processes dependent upon protein-carbohydrate recognition. 

Specific microorganisms, yeasts, and bacteria can also convert sucrose into other alcohols, as well as organic acids, amino acids, and vitamins (Scheme 15). All these biological processes have been improved with the help of modern biotechnology, making them more chemically and economically efficient and to direct them towards new and useful chemical products. The biocracking of carbohydrates has been shown to be a way for the production of biohydrogen. 223... 

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