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Amino Acids, Polypeptides, and Proteins
Amino acids are the building blocks of peptides and proteins. All amino acids contain an amine group, a carboxylic acid group, and a side chain that varies for each amino acid. The side chains differ in polarity and pKa and are important to both protein structure and function. Peptides are chains of two and up to 100 amino acids bonded by amide bonds between the carboxyl and amino groups of adjacent side chains. Proteins are comprised of one or more peptide chains, typically folded into a globular or fibrous form in a biologically functional way. Protein function is determined by its amino acid composition and its three-dimensional structure. Thermo Scientific offers a comprehensive selection of amino acid, peptide, and protein products for various research applications.
Amino acids can be classified based on the chemical properties of their side chains: aliphatic, aromatic, basic, acidic, and neutral. L-stereochemistry overwhelmingly predominates amino acids found in nature. Twenty amino acids are directly encoded by the genetic code of eukaryotes. We offer a full line of amino acids in different grades and purities. We also offer a large range of amino acid derivatives to aid in the study of how amino acid modifications affect protein activity, structure, and function.
A protected amino acid is one in which the amino group, the carboxylic acid group or both are temporarily attached to a protecting group so that the protected functional group does not react under the conditions to which the amino acid is subjected. Examples of protecting groups 9-fluorenylmethoxycarbonyl (Fmoc) and the tert-butyloxycarbonyl (Boc) groups. In peptide synthesis, by protecting the amine group of one amino acid and the carboxylic acid group of another amino acid, a specific amide bond can be formed. By repeating this process, peptides are formed. In organic synthesis, N-protected amino acids are often employed as important intermediates in asymmetric synthetic reactions, synthesis of medicinal compounds, and various polymerization reactions.
The design and synthesis of β-amino acids and of other biologically active amino acid derivatives is a challenge in current drug design. The only commonly naturally occurring β-amino acid is β-alanine. Several new β-amino acid derivatives are now available through Thermo Fisher Scientific, and many are extensively cited in the scientific literature, such as the following:
- Racemic 3-amino-3-(4-cyanophenyl)propionic acid—used in the synthesis of aromatase inhibitors, antagonists of the Bradykinin B1 receptor, and TNFα inhibitors. We supply enantiomerically pure 3-amino-3-(4-cyanophenyl)propionic acids in both R and S forms.
- Chiral propionic acid—employed in the total synthesis of several naturally occurring compounds such as (+)-(S)-dihydroperiphylline, (+)-(8S,13R)-cyclocelabenzine, (-)-dihydrocelacinnine, and (+/-)celabenzine
- (R)-3-(Boc-amino)-3-(4-bromophenyl)propionic acid—described in a patent as an AGC kinase inhibitor
Shown below are some of the β-amino acids in the Thermo Scientific product portfolio.
Unnatural amino acids (UAAs), so called because they are not found in natural polypeptide chains, are useful building blocks in candidates for drug development and in other functional materials. Among the UAAs are several new phenylalanine derivatives, now available through Thermo Scientific, which have been extensively cited in the scientific literature. For example, 4-Cyano-N-Fmoc-L-phenylalanine was used to create novel amino acids incorporating both acidic and aromatic properties. It was also used in a series of multi-step reactions to prepare peptides used in the study of the chemical and biological effects of platelet aggregation. We have expanded our comprehensive range of Boc and Fmoc protected phenylalanine derivatives.
Peptides are key regulators of many biological functions, including hormone release and many neurological processes. These compounds, which may be synthetic, are used as signaling ligands, catalysts, imaging agents, and more. Thermo Fisher Scientific offers an extensive range of peptides. Many are useful in the study of neuroscience, signal transduction, metabolism, and other essential processes.
Proteins have many different functions in biology, including molecular transport, catalysis, and cellular signaling. Proteins can also have structural functions in cells. These structural proteins are frequently found in connective tissues such as cartilage, and in hair, nails, and animal shells. Thermo Fisher Scientific offers a range of protein reagents for life science research.