Peptit

Peptit, in biochemistry, denotes a molecule composed of two or more amino acids linked by covalent peptide bonds. Short chains are typically called peptides (dipeptides, tripeptides, or oligopeptides); longer chains are referred to as polypeptides or proteins. Peptits are fundamental building blocks of biology and industry.

Peptits form by condensation reactions between the carboxyl group of one amino acid and the amino group of the next, releasing a molecule of water. The resulting amide (peptide) bond has partial double-bond character, is relatively planar, and restricts rotation, while the surrounding N-Cα bonds confer conformational flexibility to the chain.

In living organisms, peptits act as signaling molecules, hormones, neurotransmitters, antibiotics, and parts of larger proteins. Some well-known peptides include insulin, oxytocin, and various neuropeptides. The same chemistry underlies ribosomal synthesis of proteins and nonribosomal biosynthetic pathways that assemble diverse cyclic and branched peptits in microbes.

Synthesis and analysis: Peptits are routinely synthesized chemically via solid-phase peptide synthesis and assembled enzymatically in cells. In proteomics, sequencing and quantifying peptits relies on techniques such as mass spectrometry and liquid chromatography. Peptits are named by the sequence of amino acids, using three-letter or one-letter codes; the termini are designated as N-terminus and C-terminus.

Terminology varies by language; in some languages the direct equivalent of peptide is peptit. In scientific contexts, precise length and structural terms (dipeptide, oligopeptide, polypeptide) are used to distinguish short from long chains.