Avoidance of Proteolysis in Extracts

Proteolytic enzymes (or proteases, peptidases, or proteinases) hydrolyze the peptide bond in proteins and peptides. The nomenclature is imprecise, but there is a broad acceptance that endopeptidases break bonds that are “internal” in the primary sequences, whereas exopeptidases trim one, two, or perhaps three amino acids from the amino or carboxy terminus of the substrate. Every cell and subcellular compartment has its own complement of proteolytic enzymes, and in normal circumstances, the activities of the proteolytic enzymes are well regulated. When a tissue is disrupted, however, this control is lost, and the proteinases may then attack proteins at a rate that leads to a loss of those proteins within the time scale of the study. Adventitious proteolysis is a technical problem that may require modification to methodology to minimize the assault on the protein of interest ( 1 – 4 ). These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.