Amino acid | EPFL Graph Search

Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the α-amino acids, from which proteins are composed. Only 22 α-amino acids appear in the genetic code of all life. Amino acids can be classified according to the locations of the core structural functional groups, as alpha- (α-), beta- (β-), gamma- (γ-) or delta- (δ-) amino acids; other categories relate to polarity, ionization, and side chain group type (aliphatic, acyclic, aromatic, containing hydroxyl or sulfur, etc.). In the form of proteins, amino acid residues form the second-largest component (water being the largest) of human muscles and other tissues. Beyond their role as residues in proteins, amino acids participate in a number of processes such as neurotransmitter transport and biosynthesis. It is thought that they played a key role in enabling life on Earth and its emergence. Amino acids are formally named by the IUPAC-IUBMB Joint Commission on Biochemical Nomenclature in terms of the fictitious "neutral" structure shown in the illustration. For example, the systematic name of alanine is 2-aminopropanoic acid, based on the formula . The Commission justified this approach as follows: The systematic names and formulas given refer to hypothetical forms in which amino groups are unprotonated and carboxyl groups are undissociated. This convention is useful to avoid various nomenclatural problems but should not be taken to imply that these structures represent an appreciable fraction of the amino-acid molecules. The first few amino acids were discovered in the early 1800s. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound from asparagus that was subsequently named asparagine, the first amino acid to be discovered. Cystine was discovered in 1810, although its monomer, cysteine, remained undiscovered until 1884. Glycine and leucine were discovered in 1820.

Interrupted Polonovski Strategy for the Synthesis of Functionalized Amino Acids and Peptides

Jérôme Waser, Christine Alice Jacqueline Marty, Emmanuelle Madeline Dominique Allouche

The alpha-functionalization of carbamate-protected hydroxylamine glycine derivatives, acting as imine surrogates via an interrupted Polonovski reaction, is described to access functionalized amino acid derivatives. The addition of C, N, O, and S nucleophil ...

Washington2024

Aptamer-Functionalized Interface Nanopores Enable Amino Acid-Specific Peptide Detection

Nako Nakatsuka, Xinyu Zhang, Haiying Hu

Single-molecule proteomics based on nanopore technology has made significant advances in recent years. However, to achieve nanopore sensing with single amino acid resolution, several bottlenecks must be tackled: controlling nanopore sizes with nanoscale pr ...

2024

Influence of Amino Acid Substitutions in Capsid Proteins of Coxsackievirus B5 on Free Chlorine and Thermal Inactivation

Tamar Kohn, Aleksandar Antanasijevic, Kiruthika Kumar, Shotaro Torii

The sensitivity of enteroviruses to disinfectants varies among genetically similar variants and coincides with amino acid changes in capsid proteins, although the effect of individual substitutions remains unknown. Here, we employed reverse genetics to inv ...

2024