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The S−H bond in thiols is weak compared to the O−H bond in alcohols. For CH 3 X−H, the bond enthalpies are 365.07 ± 2.1 kcal/mol for X = S and 440.2 ± 3.0 kcal/mol for X = O. [ 21 ] Hydrogen-atom abstraction from a thiol gives a thiyl radical with the formula RS • , where R = alkyl or aryl.
Peptide bond formation via dehydration reaction. When two amino acids form a dipeptide through a peptide bond, [1] it is a type of condensation reaction. [2] In this kind of condensation, two amino acids approach each other, with the non-side chain (C1) carboxylic acid moiety of one coming near the non-side chain (N2) amino moiety of the other.
In organic chemistry, peptide synthesis is the production of peptides, compounds where multiple amino acids are linked via amide bonds, also known as peptide bonds. Peptides are chemically synthesized by the condensation reaction of the carboxyl group of one amino acid to the amino group of another.
A thioamide (rarely, thionamide, but also known as thiourylenes) is a functional group with the general structure R 1 −C(=S)−NR 2 R 3, where R 1, R 2 and R 3 are any groups (typically organyl groups or hydrogen). Analogous to amides, thioamides exhibit greater multiple bond character along the C-N bond, resulting in a larger rotational ...
Protein primary structure is the linear sequence of amino acids in a peptide or protein. [1] By convention, the primary structure of a protein is reported starting from the amino-terminal (N) end to the carboxyl-terminal (C) end. Protein biosynthesis is most commonly performed by ribosomes in cells. Peptides can also be synthesized in the ...
Thioesters hydrolyze to thiols and the carboxylic acid: RC(O)SR' + H 2 O → RCO 2 H + RSH. The carbonyl center in thioesters is more reactive toward amine than oxygen nucleophiles, giving amides: This reaction is exploited in native chemical ligation, a protocol for peptide synthesis. [8]
[4] [5] The amide group is called a peptide bond when it is part of the main chain of a protein, and an isopeptide bond when it occurs in a side chain, as in asparagine and glutamine. It can be viewed as a derivative of a carboxylic acid ( R−C(=O)−OH ) with the hydroxyl group ( −OH ) replaced by an amine group ( −NR′R″ ); or ...
[11] [12] A trichlorosilane based "head group", for example in a FDTS molecule, reacts with a hydroxyl group on a substrate, and forms very stable, covalent bond [R-Si-O-substrate] with an energy of 452 kJ/mol. Thiol-metal bonds are on the order of 100 kJ/mol, making them fairly stable in a variety of temperatures, solvents, and potentials. [10]