Amino acids, various

Protected Amino Acids. Various types of protected amino acids for peptide synthesis are available commercially (243). 

Various individual amino acids Various carbohydrates Alcohols and polyols Surfactants... 

The gradient in IEF is a pH gradient that is generated by electrolyte systems consisting of ampholytes. The capillary wall is coated in order to avoid electroosmosis. The IEF mode is especially suitable for the separation of zwitter ionic compounds like proteins, peptides, amino acids, various drugs, etc. After injection of the sample and application of the potential, the sample constituents migrate to a pH in the capillary... 

However, the revision of many naturally occurring amino acids is under progress. For limitation of other amino acids various methods such as ion chromatography, amino acid analysis, HPEC, and CZE are available and have to be tested case by case. In addition, tests for other non-amino acid related substances have to be developed. Possibly substances of different origin (production by synthesis, by fermentation, or by protein hydrolysis) may need different methods. In addition, a test for enantiomeric purity has to be included. 

Free and derivaiized amino acids, various neutral, basic and acidic drugs ristocetin A 289 ... 

Proteins are made up of amino acids, which are joined by peptide linkages. Although there are only 20 different naturally occurring amino acids, various combinations of these form the thousands of proteins used in metabolism. 

Animal experiments have shown that faulty nutrition, i.e. > 90% fat, < 10% protein and < 2 mg choline per day, leads to pronounced fatty fiver and even fatty cirrhosis within a few weeks. The same changes could be observed when the protein intake remained more or less normal, while extremely little methionine and choline was offered. With a partial surplus of certain foodstuffs, the special nature of the excessive nutritional components is also of considerable importance. The term partial malnutrition may, for example, be associated with a pronounced protein deficiency (and thus possibly inadequate production of lipoproteins) or a lack of lipotropic substances (such as methionine, choline, cystine, glycocoUbetaine, pyridoxine, casein and various N- or S-methylated substances). Protein deficiency has particularly severe consequences when toxic substances are absorbed at the same time or when the organism has to fight bacterial or parasitic infections. A diseased liver reacts to both a serious deficiency in and an excessive supply of different nutrients (e.g. proteins, certain kinds of amino acids, various lipids, trace elements) with unfavourable or even complicative developments during the course of disease. 

Variety of natural and unnatural amino acids Various approaches eg-, 12151... 

Thin layer chromatography is also used for direct enantiomeric resolution of D,L-arginine, D,L-histidine, d,l-lysine, D,L-valine, and D,L-leucine on silica gel plates impregnated with optically pure (IR, 3R, 5R)-2-azabicy-clo[3,3,0]octan-3-carboxylic acid, which serves as a chiral selector in the pharmaceutical industry. To successfully resolve D,L-amino acids, various combinations of aceto-nitrile-methanol-water were proposed. The spot was detected by ninhydrin (0.2% in acetone). 

Various methods have been developed for the production of amino acids. Most naturally-occurring, proteinogenic amino acids can be produced by fermentation, although chemical synthesis, isolation from hydrolyzed proteins, and enzymatic conversion are used in a few instances. For the production of non-proteinogenic or non-natural amino acids for which no metabolic pathways exist, traditional fermentation methods cannot be used without re-engineering of the metabolic pathways in the cell. For these types of amino acids, various chemical and enzymatic synthetic methods have become increasingly common. 

The modem automated amino acid analyzer based on HPLC (Hancock, 1984) can perform complete analysis in less than 60 m with a sensitivity as low as Ipmol of each amino acid. Various derivatization protocols for high performance (high-pressure) chromatography (HPLC) use fluorescent and UV-absorbing tags, such as 1-dimethylamino... 

Various L-amino acids Various Some amino acids are produced fermentatively by E. coli or C. glutamicum [16]... 

Pyrrolinones are important synthons in the preparation of many important compounds including amino acids, various alkoids and many natural products. These heterocyclic derivatives have also been shown to express anti-tumor properties. In addition, they are inhibitors of cyclooxygenase-2 (COX-2), and HIV-1 protease. They also possess several important and exploitable medicinal properties. Pyrrolinones can be synthesized from functionalized imino-alkynes via cyclohhydrocarbonylation in the presence of a zwitterionic rhodium catalyst (ZW) 106 with both high regioselectivity and chemoselectivity as well as in good overall yield (Table 2-3). This versatile reaction system allows for easy access to important synthons. ... 

Amino acid compositions for soybean and pea enzymes have been studied by several groups (see Veldink et al., 1977). Although there is general agreement for most amino acids, various values have been reported for the cysteine and cystine contents, ranging, for the soybean enzyme, from 4 (Mitsuda et al., 1967a) to 12 (Axelrod, 1974) half-cystine residues. Amino acid analyses of two isoenzymes from pea have been obtained by Eriksson and Svensson (1970) and Arens et al. (1974). 

For Determining the Sequence of amino acids various methods have been developed during the past twenty years, as discussed under peptides (Chapt. III-l). Usually the N-terminal amino acid is determined first, by labeling the amino end with the dinitrophenyl radical. Chemical degradative methods are also available that can remove one amino acid at a time, as exemplified by the Edman degradation. 

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