Members of the serine proteases are diverse with regard to their function, expression pattern and association with health and disease. Some are active in the coagulation cascade and the complement pathways while others are found specifically in the granules of cytotoxic T lymphocytes and natural killer cells (Granzymes) or in mast cells with trypsin-like specificity (Tryptases). Secreted tissue Kallikreins are cancer markers while transmembrane proteases such as Corin and Enterokinase are convertases. Their proteolytic activity is regulated by different Serpins and receptors such as uPAR and HAIs.