peptós

Peptós are short chains of amino acids linked by peptide bonds. They occur throughout biology and function in signaling, regulation, and defense. By convention, oligopeptides are short sequences often described as up to about 20–30 amino acids, while longer chains are termed polypeptides; when they fold into defined three-dimensional shapes, they form functional domains within proteins.

The basic unit is an amino acid, connected through amide (peptide) bonds between the carboxyl group of one amino acid and the amino group of the next. The order (sequence), length, and any post-translational modifications determine a peptós' properties, including charge, hydrophobicity, and conformation. Peptós can be linear or cyclic; cyclic peptós often exhibit greater stability and receptor-binding specificity.

Biosynthesis and production: In living organisms, many peptós are produced ribosomally as parts of larger proteins and released by proteolysis; others arise from non-ribosomal peptide synthases. In the laboratory, peptós are commonly made by solid-phase peptide synthesis (SPPS) or by solution-phase methods, enabling precise control of sequence and modifications.

Functions and applications: Endogenous peptós include hormones (such as oxytocin and vasopressin), neuropeptides, and antimicrobial agents. Therapeutic peptides are a rapidly growing drug class, with applications in endocrinology, oncology, and infectious disease. Peptós are used as research tools, in cosmetics, agriculture, and materials science.

Stability and challenges: Peptós are susceptible to proteolysis and often have limited oral bioavailability. Strategies to improve stability include chemical modifications (D-amino acids, N-/C-terminal alterations), cyclization, and conjugation or alternative delivery systems.