Threonine properties

Threonine, stereoisomers of, 302-303 structure and properties of, 1019 Threose. configuration of, 982 molecular model of, 294 Thromboxane B2. structure of,... 

Table 1 presents the chemical composition and some properties of both gums reported by Osman et al., 1993 and Williams Phillips, et al., 2000. Despite having different protein content, amino acid composition is similar in both gums. Recently, Mahendran et al., 2008, reported the GA amino acid composition in Acacia Senegal, being rich in hydroxyproline, serine, threonine, leucine, glycine, histidine. Table 2. 

The physical properties of the synthetic glycosyl derivatives of l-asparagine, L-serine, and L-threonine are reported in Tables I-V. Derivatives characterized otherwise, but without m.p. and optical rotation, have also been included. Whenever more than one reference is given, the physical constants are taken from the references printed in bold letters. The abbreviations used in the m.p. column are as follows foam., foaming dec., decomposing and soft., softening. 

Protein kinases differ in their cellular and subcellular distribution, substrate specificity and regulation. These properties determine the functional roles played by the very large number of protein kinases that have been found in mammalian tissues, most of which are known to be expressed in neurons [3]. The major classes of protein serine-threonine kinase in the brain, listed in Table 23-1, are covered in this chapter. The major classes of protein tyrosine kinases in the brain are discussed in Chapter 24. 

Characteristically, legume seeds are rich in protein and contain intermediate to high levels of lysine and threonine which are important in balancing the deficiencies of these essential amino acids in cereal diets. Certain legume proteins, such as soybean, also exhibit strong functional properties, especially water solubility, water and fat binding and emulsification. Thus soybean flours, protein concentrates and isolates have been used widely as nutritional supplements and functional ingredients in foods. 

A T-C polymorphism was described in the sequence of apo(a)-KIV10 (V6), corresponding to nucleotide 12,605 of the published cDNA sequence (M24). This variant results in the substitution of a methionine (ATG) with a threonine (ACG) at this position. No correlation was observed between the polymorphism and plasma Lp(a) levels. Although the Met-Thr substitution is present within the lysine binding pocket in KIV10, its effect on lysine binding properties of this kringle remains to be determined. 

Stereoisomers with more than one chiral center and which are not mirror images of each other hence, stereoisomers that are not enantiomers of each other. For example, L-threonine and D-threonine are an enantiomeric pair whereas L-threonine and D-allothreonine are a diastereomeric pair (as is L-threonine and L-allothreo-nine). Diastereomers will have similar physical, chemical, and spectral properties but those properties will not be identical. If n is the number of chiral centers, then the maximum number of stereoisomers will be equal to 2. However, the actual number for a given set of isomers may be less than 2 due to the presence of meso forms. See Enantiomer Epimer Meso Form... 

Threonine and a,7-diaminobutyric acid are present within the structure of these antibiotics. The distinguishing feature of the polymyxine group is in that they contain 4-5 free / amine groups of a,7-diaminobutyric acid, which gives them the property of a cationic detergent able to form complexes with phospholipids of cellular membranes. All polymyxines are similar in term of antibiotic action. 

Cantharidin is a toxin isolated from fish. Among its numerous biological activities, cantharidin exhibits insecticide and herbicide properties. Cantharidin and norcanthar-idin are inhibitors of serine and threonine phosphatases, which are important enzymes for the regulation of cell processes and cell proliferation. Mono- and difluoronor-... 

The biosynthesis 237,5381 involves enzymatic dehydration of serine and threonine residues in a manner similar to the formation of thiazoles and dihydrothiazoles vide supra) with or without subsequent oxidation to yield the 2-(l-aminoalkyl)oxazole-4-carboxylic acid and 2-(l-aminoalkyl)dihydrooxazole-4-carboxylic acid shown in Scheme 38. These cyclic peptides display interesting physiological properties such as cytotoxicity/541, 569,5831 antitumor activities, or antineoplastic effects/523,5291 but as for the sulfur-containing compounds the mechanism of action is not yet understood despite extensive SAR studies. 515,521,540,5431... 

Based on the properties of the side chains, the 20 amino acids can be put into six general classes. The first class contains amino acids whose side chains are aliphatic, and is usually considered to include glycine, alanine, valine, leucine, and isoleucine. The second class is composed of the amino acids with polar, nonionic side chains, and includes serine, threonine, cysteine, and methionine. The cyclic amino acid proline (actually, an imino acid) constitutes a third class by itself. The fourth class contains amino acids with aromatic side chains tyrosine, phenylalanine, and tryptophan. The fifth class has basic groups on the side chains and is made up of the three amino acids lysine, arginine, and histidine. The sixth class is composed of the acidic amino acids and their amides aspartate and asparagine, and glutamate and glutamine. 

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