Azurocidin (HBP)

Azurocidin, commonly referred to as Heparin-binding protein (HBP) or CAP37, is a 37-kDa protein stored in the secretory and azurophilic granules of neutrophils. Although it belongs to the serine protease family, it lacks proteolytic activity due to mutations in its catalytic triad. HBP is released upon neutrophil activation and acts as a potent mediator of vascular leakage by inducing cytoskeletal rearrangements in endothelial cells. It also functions as a chemoattractant for monocytes and exhibits broad-spectrum antimicrobial activity. In clinical settings, HBP is a critical biomarker for the early detection of sepsis and organ dysfunction, as its levels rise before clinical signs of circulatory failure. It is being investigated as a therapeutic target to mitigate systemic inflammatory damage and vascular collapse in conditions like septic shock. Drugs such as heparin and albumin can bind and neutralize HBP, potentially reducing its pathological effects on the vascular endothelium.

Other names

General heparin-binding proteinsHeparin-binding proteinCAP37Cationic antimicrobial protein 37 kDaAZU1

Neutralization of HBP-induced vascular permeability through competitive binding and sequestration, preventing HBP from interacting with endothelial cell surfaces and inducing cytoskeletal rearrangements.