noncleaved

Noncleaved refers to a molecule that has not undergone proteolytic cleavage, a process that typically removes signal peptides, propeptides, or activation segments from a larger precursor. The term is used across biology to describe proteins, peptides, and other macromolecules that remain in or are observed in their intact, unprocessed form.

In protein maturation, many secreted and membrane proteins are synthesized as larger precursors and later processed by proteases to produce active or mature forms. A noncleaved form may represent an immature, inactive, or alternative functional state, depending on the protein and cellular context. For some proteins, cleavage is essential for activity, while for others the noncleaved form can retain function or serve as a regulatory reservoir.

In virology, noncleaved precursors are a notable concept. For example, certain viral glycoproteins are produced as a single noncleaved precursor that must be cleaved by host or viral proteases to become fusion-competent. The cleavage state can influence infectivity, tropism, and pathogenic potential.

In research and medicine, distinguishing noncleaved from cleaved forms helps reveal protein maturation pathways, enzymatic regulation, and disease mechanisms. Techniques such as Western blotting with cleavage-site–specific antibodies or mass spectrometry are used to assess the cleavage state of proteins and its biological consequences. Abnormal cleavage can be associated with disorders ranging from metabolic diseases to viral pathogenicity. See also proteolysis, zymogen, signal peptide, and maturation.