Lowlysine

Lowlysine is a descriptive term used in biochemistry and proteomics to refer to proteins, peptides, or regions within proteins that contain a lower-than-typical proportion of the amino acid lysine (represented by the letter K). It is not a formal classification or a named gene, but rather a characterization that researchers apply when lysine content is notably reduced compared with reference sequences or expected amino acid composition.

In proteomics, the concept is relevant because lysine residues are common sites for post-translational modification, such as ubiquitination and acetylation, and they also serve as frequent cleavage points for proteolytic enzymes like trypsin. Regions with few lysines therefore exhibit fewer tryptic cleavage sites, which can influence peptide generation, fragmentation patterns, and the efficiency of mass spectrometry analysis. Low-lysine regions can arise from evolutionary pressures, structural constraints, or functional requirements that favor other amino acids in particular protein domains.

Measurement and analysis typically involve determining amino acid composition from protein or peptide sequences, followed by comparative analyses to identify regions that are unusually lysine-poor. When encountered in experiments, low-lysine content may necessitate alternative proteases or digestion strategies to achieve adequate peptide coverage in mass spectrometry workflows.

See also: Lysine, Protein composition, Post-translational modification, Proteomics, Trypsin.