Amino-functional polysaccharides

Monosaccharides may possess functionalities other than hydroxyls. Amino sugars are aldoses or ketoses which have a hydroxyl group replaced by an amino functionality. 2-Amino-2-deoxy-glucose is one of the most abundant amino sugars it is a constituent of the polysaccharide chitin. It also appears in mammalian glycoproteins, linking the sugar chain to the protein. Monosaccharides may also be substituted with sulfates and phosphates. Furthermore, deoxy functions can often be present, and important examples of this class of monosaccharides are L-fucose and L-rhamnose. 

Method D. The polysaccharide was hydrolyzed with acetic acid to fragments having between 5 and 15 repeating units. After purification, ethylendiamine reacts at the terminal reducing end introducing a terminal amino function. Similarly to method A, the reaction with ADH introduced a spacer having terminally a very reactive hydrazide function [104]. 

Scientific reports dealing with functional effects of seaweed proteins, peptides, amino acids, polysaccharides, phytochemicals, lipids, and minerals greatly endorse the efforts toward development of "health foods" using seaweeds. Table 1.1 provides some seaweed species studied and recognized for their richness in functionally important molecular groups. Evaluation of functional properties requires a clear idea about their biochemical composition, and it provides a platform to have an inspiration to decide on the molecules responsible for different biological activities. 

Polystyrene-block-poly(L-lysine), polybutadiene-block-poly(L-lysine) [72], and block copolymers of polystyrene or polybutadiene with poly(carboxybenzoxy-L-lysine) [73] were also synthesized by Gallot and coworkers and evidence for lamellar assembUes were presented. Polysaccharide-block-polypeptide rod-coil systems were obtained by polymerizing the IV-carboxyanhydrides of Y -benzyl-L-glutamate from the asparagine a-amino function of carbohydrate fractions of ovomucoid (a glycoprotein extracted from hen egg white). Lamellar assembUes in concentrated solutions and in... 

Most commercial polysaccharides, such as cellulose, dextran, pectin and starch are either neutral or acidic, but chitosan is a basic polysaccharide [112]. In neutral or basic pH conditions, chitosan displays free amino groups and is insoluble in water, while in acid conditions becomes water soluble due to the protonation of amino functions, and its solubility depends on the distribution of free amino and A -aceyl groups [111,121-123]. 

Other immobilization methods are based on chemical and physical binding to soHd supports, eg, polysaccharides, polymers, glass, and other chemically and physically stable materials, which are usually modified with functional groups such as amine, carboxy, epoxy, phenyl, or alkane to enable covalent coupling to amino acid side chains on the enzyme surface. These supports may be macroporous, with pore diameters in the range 30—300 nm, to facihtate accommodation of enzyme within a support particle. Ionic and nonionic adsorption to macroporous supports is a gentle, simple, and often efficient method. Use of powdered enzyme, or enzyme precipitated on inert supports, may be adequate for use in nonaqueous media. Entrapment in polysaccharide/polymer gels is used for both cells and isolated enzymes. 

Note The amino acid residues of lysine (K) and arginine (R) which may be responsible for the binding of POs to polysaccharides are in bold. According to Demand et al. (2002), the mutual substitution of these amino acids has no influence on the sorption properties of the ATg08770 PO of Arabidopsis with pectins, and the deletion of the fragment results in the loss of this function. 

Besides water, the diet must provide metabolic fuels (mainly carbohydrates and lipids), protein (for growth and turnover of tissue proteins), fiber (for roughage), minerals (elements with specific metabolic functions), and vitamins and essential fatty acids (organic compounds needed in small amounts for essential metabolic and physiologic functions). The polysaccharides, tri-acylglycerols, and proteins that make up the bulk of the diet must be hydrolyzed to their constituent monosaccharides, fatty acids, and amino acids, respectively, before absorption and utilization. Minerals and vitamins must be released from the complex matrix of food before they can be absorbed and utifized. 

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