DesArg

DesArg is a biochemical term used in peptide and protein nomenclature to indicate the removal or absence of an arginine (Arg) residue from a peptide sequence. The prefix des- (from Latin, meaning "without") combined with the one-letter or three-letter code for arginine denotes that a specific arginine has been cleaved or is missing; for example, des-Arg9-bradykinin describes bradykinin lacking the ninth amino-acid arginine.

The designation commonly applies to proteolytic processing events, especially C‑terminal cleavage by carboxypeptidases that remove a terminal arginine. Such processing can markedly change a peptide’s biological activity, receptor selectivity, half-life, and physicochemical properties. A well-known case is the conversion of bradykinin to des-Arg9‑bradykinin, which shifts activity from the B2 kinin receptor to the inducible B1 receptor implicated in inflammation and pain.

DesArg variants are of interest in research, diagnostics, and drug development. They serve as biomarkers of protease activity in physiological and pathological contexts, and synthetic des-Arg analogs are used to probe receptor function or to design receptor-selective agents. Analytical techniques such as mass spectrometry, peptide sequencing, and targeted immunoassays are employed to detect and quantify des-Arg peptides.

In nomenclature practice, the term may appear with variations in capitalization and punctuation (e.g., desArg, des-Arg). It is applied broadly across peptide classes whenever the absence of an arginine residue is functionally or structurally relevant.