Biopolymers classes

At the present time, although there are several applications of CEC-PEC to biopolymer classes, these are to be considered only preliminary and not necessarily fully optimized in all possible parameters. At times. 

The analyte is typically dissolved in a solution containing an excess of the matrix that contains a chromophore absorbing at the laser wavelength. UV lasers are mainly used for protein analysis, but for certain biopolymer classes such as polynucleotides IR lasers are also employed [8, 34]. Several sample preparation techniques have been developed to place a small amount of solution on the target. The MALDI process is depicted schematically in Fig. 10.3. Although details of the mechanism are unknown at presenL it is generally accepted that the matrix ab-... 

Proteins, as a biopolymer class, are one of the main structural and regulatory units in living organisms. Proteins consist of linear chains of alpha amino acid... 

The book addresses the most important biopolymer classes like polysaccharides, lignin, proteins and polyhydroxyalkanoates as raw materials for bio-based plastics, as well as materials derived from bio-based monomers like lipids, poly(lactic acid), polyesters, polyamides and polyolefines. Additional chapters on general topics - the market and availability of renewable raw materials, the importance of bio-based content and the issue of biodegradability - will provide important information related to all bio-based polymer classes. 

Polymers may occur naturally as biopolymers or may be produced synthetically. The main biopolymer classes are polyprenes, nucleic acids, proteins, polysaccharides, and lignins. Biopolymers are skeletal or support materials, messengers, transport media, and storage reserve materials, or are just simply products of metabolism. 

Macromolecules are sometimes divided into natural and synthetic macromolecules. Synthetic macromolecules are normally composed of one to three different types of monomeric units, whereas natural macromolecules or biopolymers may contain many different types. Four main classes of biopolymers exist polyprenes, polysaccharides, nucleic acids, and proteins. Polyprenes (see Section 25.3.2) contain only one type of monomeric unit They are homopolymers and correspond in constitution and configuration to the synthetic polymers. Polysaccharides (see Chapter 31) are either homopolymers or copolymers with up to five different types of monomeric units. Proteins (see Chapter 30) may consist of up to 20 different monomeric units per macromolecular chain Nucleic acids are composed of relatively few types of monomeric units (see Chapter 29). The combination of units of these four types of biopolymers may lead to other biopolymer classes, e.g., nucleoproteins, glycoproteins, etc. 

A biopolymer produced by a particular strain of bacteria is becoming widely used as a substitute for clay in low-solids muds. Since the polymer is attacked readily by bacteria, a bactericide such as paraformaldehyde or a chlorinated phenol also must be used with the biopolymer. The system has more stable properties than the extended bentonite system, because biopolymer exhibits good rheological properties in its own right, and has a better tolerance to salt and calcium. The system can be formulated to include salt, such as potassium chloride. Such a system, however, would then be classed as a nondispersed inhibitive fluid. 

Interestingly, it was in a different context that both Seebach and Gellman approached the field of yS-peptides. Seebach s initial interest in yS-peptides stemmed from their resemblance to poly(yS-hydroxy alkanoates) (PHA), an ubiquitous class of biopolymers of which poly[(P)-3-hydroxybutanoic acid] (8, PHB) is the most common (for reviews see [37, 38]). 

Elastomeric polypeptides are a class of very interesting biopolymers and are characterized by mbber-like elasticity, large extensibility before rupture, reversible deformation without loss of energy, and high resilience upon stretching. Their useful properties have motivated their use in a wide variety of materials and biological applications. Here, we focus on two elastomeric proteins and the recombinant polypeptides derived thereof. 

The first elastomeric protein is elastin, this structural protein is one of the main components of the extracellular matrix, which provides stmctural integrity to the tissues and organs of the body. This highly crosslinked and therefore insoluble protein is the essential element of elastic fibers, which induce elasticity to tissue of lung, skin, and arteries. In these fibers, elastin forms the internal core, which is interspersed with microfibrils [1,2]. Not only this biopolymer but also its precursor material, tropoelastin, have inspired materials scientists for many years. The most interesting characteristic of the precursor is its ability to self-assemble under physiological conditions, thereby demonstrating a lower critical solution temperature (LCST) behavior. This specific property has led to the development of a new class of synthetic polypeptides that mimic elastin in its composition and are therefore also known as elastin-like polypeptides (ELPs). 

Synthetic examples include the poly(meth)acrylates used as flocculating agents for water purification. Biological examples are the proteins, nucleic acids, and pectins. Chemically modified biopolymers of this class are carboxymethyl cellulose and the lignin sulfonates. Polyelectrolytes with cationic and anionic substituents in the same macromolecule are called polyampholytes. 

MnP is the most commonly widespread of the class II peroxidases [72, 73], It catalyzes a PLC -dependent oxidation of Mn2+ to Mn3+. The catalytic cycle is initiated by binding of H2O2 or an organic peroxide to the native ferric enzyme and formation of an iron-peroxide complex the Mn3+ ions finally produced after subsequent electron transfers are stabilized via chelation with organic acids like oxalate, malonate, malate, tartrate or lactate [74], The chelates of Mn3+ with carboxylic acids cause one-electron oxidation of various substrates thus, chelates and carboxylic acids can react with each other to form alkyl radicals, which after several reactions result in the production of other radicals. These final radicals are the source of autocataly tic ally produced peroxides and are used by MnP in the absence of H2O2. The versatile oxidative capacity of MnP is apparently due to the chelated Mn3+ ions, which act as diffusible redox-mediator and attacking, non-specifically, phenolic compounds such as biopolymers, milled wood, humic substances and several xenobiotics [72, 75, 76]. 

The three major classes of biopolymers found in eukaryotic systems are nucleic acids, proteins, and polysaccharides. The latter class is the most complex with respect to structural and stereochemical diversity. Polysaccharides indeed possess a massive information content. Furthermore, polysaccharides are commonly found in nature covalently attached (conjugated) to other biomolecules such as proteins, isoprenoids, fatty acids, and lipids.1... 

Carbohydrates A class of biopolymers whose building blocks are composed of simple sugars such as glucose and fructose. These compounds contain only carbon, hydrogen, and oxygen. 

The first reported molecular dynamics simulations of carbohydrates began to appear in 1986, with the publication of studies of the vacutim motions of a-D-glucopyranose (9), discussed below, and the dynamics of a hexa-NAG substrate bound to lysozyme (IQ), which are described in greater detail in the chapter by Post, et al. in this voltime. Since that time, simulations of the dynamics of many more carbohydrate molecules have been undertaken. A number of these studies are described in subsequent chapters of this voltime. The introduction of this well developed technique to problems of carbohydrate structure and function could contribute substantially to the understanding of this class of molecules, as has been the case for proteins and related biopolymers. 

Poly(3-hydroxybutyrate) is a biopolymer produced by numerous bacteria in nature as an intercellular carbon and energy reserve and belongs to the class of poly (hydroxyalkanoate)s (PHAs). In 1925, the French microbiologist Maurice Lemoigne discovered and characterized PHB extracted from Bacillus megaterium. However, it is produced by a various number of microorganisms such as Cupriavidus necator or Ralstonia eutroph. PHAs are biodegradable polyesters with a structure as shown in Fig. 1. 

Mikes O (1988) High-performance liquid chromatography of biopolymers and biooligomers. Part A principles, materials and techniques Part B Separation of individual compoimd classes. J Chromat Library. Elsevier, Amsterdam, vol. 41A and vol. 41B Oliver RWA (ed.) (1989) HPLC of macromolecules a practical approach. IRL Press, Oxford... 

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