Cterminaaliset

Cterminaaliset is a term used in Finnish to describe elements associated with the C-terminus of biomolecules, most often proteins or peptides. The C-terminus is the end of a polypeptide chain that carries a free carboxyl group, opposite the N-terminus.

In biochemistry, C-terminaaliset motifs are short amino acid sequences located at the extreme C-terminus that can influence protein localization, stability, interactions, or degradation. A well-known example is the peroxisomal targeting signal type 1 (PTS1), a tripeptide at the C-terminus (commonly SKL) that directs proteins to peroxisomes. Other C-terminal signals vary among organisms and contexts and can be involved in processes such as endosomal sorting or proteolytic processing.

Practically, the term can also describe tags or modifications added to the C-terminus of a protein for research purposes. Such C-terminal tags (for example, affinity tags or fluorescent markers) enable detection, purification, or localization studies without altering the N-terminus of the molecule. In proteomics, C-terminal peptides are often analyzed to map proteolytic cleavage sites and terminus heterogeneity, contributing to a detailed view of protein processing.

The usage of Cterminaaliset is primarily found in Finnish-language scientific literature, aligning with terminology that distinguishes C-terminus from N-terminus. Related concepts include N-terminaaliset, termini, and various protein targeting signals.