Peptiidideks

Peptiidideks, commonly known as peptides, are short polymers of amino acids linked by peptide bonds. They range from dipeptides (two amino acids) to oligopeptides, with longer chains typically described as polypeptides or proteins. Peptiidideks participate in nearly all biological processes and can function as hormones, neurotransmitters, signaling molecules, enzyme inhibitors, or antimicrobial agents.

Each peptide chain has an N-terminus and a C-terminus; peptide bonds form through condensation between the carboxyl group of one amino acid and the amino group of the next. The sequence and length of a peptide determine its three-dimensional shape, stability, and biological activity.

Biosynthesis and production: In cells, ribosomes translate mRNA into polypeptide chains that may be processed into mature peptides. Some organisms also use non-ribosomal peptide synthesis to create diverse peptides with unusual amino acids or cyclic structures. Chemically, peptides can be synthesized by solid-phase methods for research, therapeutics, or diagnostic use.

Functions and examples: Peptiidideks fulfill roles as hormones (for example, insulin is a peptide hormone), neurotransmitters, receptor ligands, antimicrobial peptides, and enzyme inhibitors. Small peptides like bradykinin act as signaling mediators, while larger polypeptides can serve structural or regulatory functions.

Applications and analysis: Peptide-based drugs and diagnostics are a significant field in medicine and biotechnology. Peptides are studied using techniques such as mass spectrometry and high-performance liquid chromatography. Their stability is influenced by proteolysis; modifications like terminal amidation, incorporation of D-amino acids, cyclization, or pegylation can enhance longevity.

See also: proteins, amino acids, peptide synthesis.