Peptide Bond

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Related to Peptide Bond: Dipeptide bond

peptide bond

[′pep‚tīd ‚bänd]
(organic chemistry)
A bond in which the carboxyl group of one amino acid is condensed with the amino group of another to form a ‒CO·NH‒ linkage. Also known as peptide linkage.

Peptide Bond


(also peptide linkage), an amide bond that arises during the formation of proteins and peptides when the α-amino group (—NH2) of one amino acid interacts with the α-carboxyl group (—COOH) of another amino acid:

where R1 and R2 are molecular parts that differ from one amino acid to another. The —CO—NH— group in proteins exhibits a keto-enol tautomerism.

The presence of peptide bonds in proteins and peptides was first proposed by A. Ia. Danilevskii and E. Fischer and later confirmed by chemical and physical data. Owing to tautomerism, the peptide bond exhibits a partial (40-percent) similarity to the double (conjugate) bond, which is indicated by the shorter length (1.32 A) of the peptide bond than of the single —C—N— bond (1.47 Å). The partially conjugate nature of the —C—N— bond determines the flat configuration of the —CO—NH— group (all four atoms are coplanar) and the existence of the trans and cis forms:

The greater stability of the trans form has been proved experimentally.

The enzymatic formation of peptide bonds in living cells occurs during protein biosynthesis. Laboratory methods have been developed for the chemical and enzymatic synthesis and cleavage of peptide bonds, thereby making it possible to synthesize a number of biologically active peptides and to determine the amino-acid sequence for many proteins and peptides.


References in periodicals archive ?
Alkaline relaxers induce so much damage to African hair not only because they break hydrogen bonds, salt linkages, disulfide bonds, and peptide bonds, but also because a large number of the broken bonds break irreversibly and, as a consequence, the hair fibers lose between 40-60% of their mechanical strength.
The biuret test is a chemical test used for detecting the presence of peptide bonds.
The detection is based on ultraviolet absorbance measurements at 200 rim (Capillarys, Sebia) or at 214 nm (Paragon 2000, Beckman Coulter), which correspond to the absorption of peptide bonds in proteins.
Arthred is a protein consisting of a series of 19 different amino acids joined by peptide bonds.
My work shows how you can take information that exists in base pairs [as in the hydrogen-bonded pairs in DNA] and use it to drive chemical reactions that make amide and peptide bonds [as in proteins]," Rebek says.
The technology is derived from solid phase peptide synthesis, but with the crucial difference that adjacent monomers are connected through pairs of bonds, rather than through single peptide bonds, thus forming rigid, spiro-ladder oligomers instead of floppy peptide chains capable of assuming numerous shapes.
Peptides are short polymers of amino acid monomers linked together by peptide bonds.
In hair, the keratin in the cortex has peptide bonds and hydrogen bonds that supply strength and elasticity to the cortex and help keep it together.
Detection is based on ultraviolet absorbance at 200 nm (Capillarys, Sebia) or 214 nm (Paragon 2000, Beckman Coulter), which corresponds to the absorption of peptide bonds in proteins.