Amino acids carboxylic acid group

The Critical Amino Acid Carboxylic Acid Group. 212... 

An alternative involves uncharged amino and carboxylic acid groups. 

In order to identify tyrosine derivatives that would lead to polymers that are processible, mechanically strong, and also biocompatible, we initiated a detailed investigation of the structure-property relationships in polyiminocarbonates and polycarbonates. Since the amino and carboxylic acid groups of tyrosine dipeptide (the N and C termini) provide convenient attachment points, selected pendent chains can be used to modify the overall properties of the polymers. This is an important structural feature of tyrosine dipcptide derived polymers. 

Figure 1. Molecular structures of Bisphenol A and fully protected tyrosine dipeptide. The amino and carboxylic acid groups of the dipeptide are rendered unreactive by protecting groups (schematically represented by X and Y). This leaves the phenolic hydroxyl groups as the only reactive sites of the molecule.

Amino and carboxylic acid groups at the end of chains, or on side chains (wool)... 

The structures of peptides and proteins usually contain numerous amino and carboxylic acid groups. Consequently, water soluble proteins in aqueous solution can form differently charged structures and zwitterions depending on the pH of the solution (see 1.2.2). The pH at which the latter occurs is known as the isoelectric point (p/) of the protein (Table 1.3). The nature of the charge on the structures of peptides and proteins has a considerable effect on their solubility... 

The presence of amino and carboxylic acid groups conveniently protected allows for the coupling of the SAAs building blocks to form sugar-peptide hybrids. One or more amino acids of the peptidic backbone can be replaced by the sugar units, thus incorporating the conformation-... 

Many organosulfur compounds can be resolved into optically active forms (enantiomers) owing to the presence of a chiral (asymmetric) sulfur atom 5 important examples include sulfoxides and sulfonium salts. Chiral sulfoxides containing amino or carboxylic acid groups have been resolved by formation of the diastereoisomeric salts with d-camphor-10-sulfonic acid or d-brucine. The salts can then be separated by fractional crystallisation and the free optically isomeric sulfoxides liberated by acid hydrolysis. However, a more convenient synthetic procedure for the preparation of chiral sulfoxides of high optical purity is Andersen s method (see p. 30). 

A variation on the diamine/dicarboxylic acid theme is to incorporate the amino and carboxylic acid groups into the same molecule, much as Nature does in amino acids. Nylon 6 is a polyamide derived by heating 6-aminohexanoic acid. 

FIGURE 3.59 Schematic representations of alkane SAMs immobilized (a) on Si-wafers by trialkoxysilane groups and (b) gold wafer by thiol groups, where X— functional (terminal) group like amino or carboxylic acid groups. 

Reactions involving specific structural features, such as keto, amino, or carboxylic acid groups. 

Proteins are composed of a-amino acids, carboxylic acids with an amino group on the a-carbon atom. Peptides consist of a few linked amino acids. 

Condensation polymerisation between the amino and carboxylic acid groups in amino acids produces a polypeptide or protein. The amide links in these polymers are known as peptide links (also known as peptide bonds). 

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