Amino acids biology

The title compound is a key C6 building block. Several labs have prepared novel a-amino acids, biological probes and other interesting compounds using the D-diepoxide as a key intermediate.3 An efficient route to the L-enantiomer provides a pathway to compounds with the opposite configuration, one not readily available from commercial sources, and a valuable probe of stereochemistry in biological systems and reaction mechanism. 

For P-amino acids, biological resolutions have been developed, but because the stereogenic center is not easily epimerized, as in a-amino acids, this approach will probably have to wait for a large value or volume product before it is exploited. 

Amino acid side chains, nucleic acids (low pH) Biological polyamines Amino acids, biological polyamines Ammonium ion... 

W. B. Gratzer, in Poly-a-amino acids. Biological Macromolecules Series" (G. D. Fasman, ed.), pp. 177-238. Dekker, New York, 1967. 

Many important processes are thermodynamically unfavorable, or nonspontaneous. Assembling many small amino acid molecules into a large protein molecule is an example of a nonspontaneous process. Yet biological organisms do assemble proteins from amino acids. Biological organisms accomplish many similar nonspontaneous processes. How do they do this ... 

Most biological catalysts are enzymes, i.e., proteins, which are macromolecules (polypeptides) fonned by biopolymerization of amino acids (with elimination of water) some enzymes are huge, with hundreds of monomer units. The 20 amino acid monomers occurring in nature. 

Biological infonnation is also concerned witli tire analysis of biological messages and tlieir import. The fundamental premise of tire protein-folding problem section C2.14.2.2 is tliat tire full tliree-dimensional arrangement of tire protein molecule can be predicted, given only tire amino acid sequence, together witli tire solvent composition, temperature and pressure. One test of tire validity of tliis premise is to compare tire infonnation content of tire sequence witli tire infonnation contained in tire stmcture [169]. The fonner can be obtained from Shannon s fonnula ... 

Proteins are biopolymers formed by one or more continuous chains of covalently linked amino acids. Hydrogen bonds between non-adjacent amino acids stabilize the so-called elements of secondary structure, a-helices and / —sheets. A number of secondary structure elements then assemble to form a compact unit with a specific fold, a so-called domain. Experience has shown that a number of folds seem to be preferred, maybe because they are especially suited to perform biological protein function. A complete protein may consist of one or more domains. 

The protein folding problem is the task of understanding and predicting how the information coded in the amino acid sequence of proteins at the time of their formation translates into the 3-dimensional structure of the biologically active protein. A thorough recent survey of the problems involved from a mathematical point of view is given by Neumaier [22]. 

Example Miller and Rich investigated the conformational consequences of substitution s on an amino acid in cyclosporin A. an importan t iininunosnppressive dnig. One of th e ammo acids iii this cyclic iin decapeptide is (2.v, ir. 4r, 5f )-3-nydroxy-4-methyl-2-(methylamino)-6-octenoic acid (MeBmtli. It is essential for biological activitv. 

Needleman S B and C D Wunsch 1970. A General Method Applicable to the Search for Similarities in the Amino Acid Sequences of Two Proteins. Journal of Molecular Biology 48 443-453. 

Sulfur deficiency usually is not a problem for mminants because the mminal microflora can utilize sulfur-containing amino acids. A deficiency can occur, however, when an NPN source is fed. L-Methionine [63-68-3] is the most biologically available source of sulfur (21). Various sulfates are intermediate in sulfur avadabiHty, and elemental sulfur is the least available source of sulfur. 

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