Amino acids definition

For the purpose of this chapter, all amino acids containing side chains that differ from the L-a-amino acids will be designated as either unusual or nonprotein amino acids. This is due to the observation that these unusual amino acids are generally not found to be the constituents of proteins. The scope of this chapter is limited to nonprotein L-a-amino acids. The definition of nonprotein amino acid is not absolute and, therefore, the... 

NOM is common in sediments, soils, and near ambient (<50 °C) water. The materials result from the partial decomposition of organisms. They contain a wide variety of organic compounds, including carboxylic acids, carbohydrates, phenols, amino acids, and humic substances (Drever, 1997, 107-119 Wang and Mulligan, 2006, 202). Humic substances are especially important in interacting with arsenic. They result from the partial microbial decomposition of aquatic and terrestrial plants. The major components of humic substances are humin, humic acids, and fulvic acids. By definition, humin is insoluble in water. While fulvic acids are water-soluble under all pH conditions, humic acids are only soluble in water at pH >2 (Drever, 1997, 113-114). 

Similarly, poly-(.S )-leucine and other polymeric amino acids with definite chain length were prepared and used in the same way28. Poly-(5)-leucinc has also been used in enantioselective hydroesterifications (Section D. 1.5.8.). 

CAS 73-32-5 EINECS/ELINCS 200-798-2 Synonyms Acetic acid, amino-s-butyl- 2-Amino-3-methylpentanoic acid L-2-Amino-3-methylpentanoic acid 2-Amino-3-methylvaleric acid a-Amino-p-methylvaleric acid Isoleucine (INCI) Norvaline, 3-methyl- Valeric acid, 2-amino-3-methyl Classification A natural protein amino acid Definition Commercial prod, is the naturally occurring L(+)-enantiomer Empirical C6H13NO2... 

Synonyms Amides, palm oil, N-(2-hydroxypropyl)- N-(2-Hydroxypropyl) palm oil acid amide Monoisopropanolamine palm oil acid amide Palm oil acid amide, N-(2-hydroxypropyl)- Palm oil acid monoisopropanolamide Definition Mixt. of isopropanolamides of the fatty acids derived from palm oil Formula RCONHCH2CH3CHOH where RCO- rep. fatty acids derived from palm oil Uses Emulsifier, emulsion stabilizer, surfactant, vise, control agent in cosmetics Palmamidopropyl betaine Synonyms 1-Propanaminium, N-carboxymethyl-N,N-dimethyl-3-amino-, N-(palm-oil acyl) derive., hydroxides, inner salts Classification Zwitterion (inner salt)... 

WG-160,WG-325. See Mica W.G.S. Cetyi Paimitate. See Cetyl pa Imitate l/V.G.S. Synaceti 116 NF/USP. See Cetyl esters WH-31. See Aluminum hydroxide Wheat Amino 30. See Wheat amino acids Wheat amino acids Synonyms Amino acids, wheat Definition Mixt. of amino acids from complete hydrolysis of wheat protein Uses Botanical in cosmetics moisturizer, humectant for skin and hair conditioners Features Substantive... 

Glycine itself is almost neutral, and requires very little sodium hydroxide to give a pink colour with phenolphthalein some other amino-acids, e.g., glutamic acid, aspartic acid, etc., are definitely more acidic and consequently require more alkali for this purpose cf. footnote, p. 380). 

HyperChem uses the improper dihedral angle formed by central atom - neighbor 1 - neighbor 2 - neighbor 3, where the order of neighbors is how they appear in a HIN file. Not all planar atoms customarily have associated improper torsions. The order of atoms is arbitrary but has been consistently chosen by the original authors of the CHARMM force field. The templates contain equivalent CHARMM definitions of improper torsions for amino acids. Improper dihedral angles cannot be defined that do not have a central atom, as is sometimes done in CHARMM calculations. 

Short chains of amino acid residues are known as di-, tri-, tetrapeptide, and so on, but as the number of residues increases the general names oligopeptide and polypeptide are used. When the number of chains grow to hundreds, the name protein is used. There is no definite point at which the name polypeptide is dropped for protein. Twenty common amino acids appear regularly in peptides and proteins of all species. Each has a distinctive side chain (R in Figure 45.3) varying in size, charge, and chemical reactivity. 

These are the definitions of the two characteristic dissociation constants normally expressed in terms of p K. When three dissociating groups are present in a molecule there are three piC values, ie, pfC, P 3- knowledge of these piC values is important in the separation or isolation of each amino acid by ion-exchange chromatography. 

Different side chains have been found to have weak but definite preferences either for or against being in a helices. Thus Ala (A), Glu (E), Leu (L), and Met (M) are good a-helix formers, while Pro (P), Gly (G), Tyr (Y), and Ser (S) are very poor. Such preferences were central to all early attempts to predict secondary structure from amino acid sequence, but they are not strong enough to give accurate predictions. 

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