elastase

Elastase refers to a group of serine proteases that preferentially cleave elastin, though many elastases also act on a variety of other proteins. In humans, the principal members are pancreatic elastase I and several neutrophil elastases, such as neutrophil elastase, produced during inflammatory responses. Pancreatic elastase is secreted by the exocrine pancreas as an inactive proenzyme and becomes active after proteolytic processing in the small intestine, contributing to digestion. Neutrophil elastases are stored in azurophilic granules of neutrophils and released upon activation, where they participate in microbial killing and tissue remodeling but can cause collateral damage if not properly regulated.

Elastases are serine proteases characterized by a catalytic triad of histidine, aspartate, and serine in their active sites. Their activity is tightly controlled by endogenous inhibitors, including alpha-1 antitrypsin (SERPINA1) in the lungs, secretory leukocyte protease inhibitor (SLPI), and alpha-2-macroglobulin. Imbalance between elastases and inhibitors can lead to tissue injury; a classic example is lung damage in alpha-1 antitrypsin deficiency, which can result in emphysema.

Clinical relevance includes the role of neutrophil elastase in inflammatory lung diseases such as chronic obstructive pulmonary disease and cystic fibrosis, where excess elastase activity contributes to extracellular matrix degradation and airflow limitation. In contrast, measurement of pancreatic elastase activity in stool serves as a diagnostic marker of exocrine pancreatic insufficiency, with low levels indicating impaired pancreatic function.

Elastase activity is also a focus in research on inflammation, tissue remodeling, and host defense, and its regulation remains a therapeutic target in diseases characterized by excessive proteolysis.