Information AboutProline |
| CATEGORIES ABOUT PROLINE | |
| proteinogenic amino acids | |
| glucogenic amino acids | |
| cyclic amino acids | |
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L-Proline is one of the twenty Proteinogenic units which are used in living organisms as the building blocks of Protein s. The other nineteen units are all primary Amino Acid s, but due to the (3-carbon) cyclic sidechain binding back to the nitrogen of the backbone, proline lacks a primary Amine group (−NH2). The nitrogen in proline is properly referred to as a secondary Amine . Proline is sometimes called an Imino Acid , but this is not correct, as Imine s contain a carbon-nitrogen double bond. The side chain binding to the nitrogen prevents rotation around the phi Torsion Angle , giving proline unique structural properties. Proline is a non-polar amino acid. In proteins it does not have a hydrogen on the amide group and can therefore not act as a Hydrogen Bond donor. Proline can act as a structural disruptor for ( α) Helices , and as a turning point in β Sheets . Multiple prolines and/or Hydroxyproline s in a row can create a ''proline helix''; this is the predominant structure in Collagen . Sequences of proline and 2-aminoisobutyric Acid (Aib) form a helical turn structure. Proline is Biosynthetically derived from the amino acid L- Glutamate and its direct precursor is the real Imino Acid (''S'')-Δ1-pyrroline-5-carboxylate (P5C). Proline and its derivatives are often used as asymmetric catalysts in organic reactions. The CBS Reduction or proline catalysed Aldol Condensation are prominent examples. EXTERNAL LINKS |
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