Calcium endopeptidases

Cohen AJ, Bunn PA, Franklin W, Magill-Solc C, Hartmann C, Helfrich B, Gilman L, Folkvord J, Helm K, Miller YE (1996) Neutral endopeptidase Variable expression in human lung, inactivation in lung cancer, and modulation of peptide-induced calcium flux. Cancer Res 56(4) 831-839. 

This enzyme [EC 3.4.22.8], also referred to as clostridio-peptidase B, is an endopeptidase belonging to the peptidase family Cll that has been isolated from the bacterium Clostridium histolyticum. It catalyzes the hydrolysis of peptide bonds with a preference for the Arg—Xaa bond (including the Arg—Pro bond), but not the Lys— Xaa peptide bond. This calcium ion-activated enzyme is inactivated by EDTA. 

To improve the absorption of peptides and proteins, the employment of different enzymatic inhibitors has been suggested. For example, some authors have demonstrated the usefulness of inhibitors of both exo- and endopeptidases to promote calcitonin absorption across rat vaginal mucosa [93]. A direct relationship was found between the effect of peptidase inhibitors of in vitro degradation constant of calcitonin in vaginal mucosa homogenates and in vivo promotion of drug absorption, indicated by the decrease in plasma calcium levels after calcitonin administration in rats. The peptidase inhibitors tested were pepstatin, bestatin, and leupeptin. 

Park, O. and Allen, J.C. 1998. Preparation of phosphopeptides derived from as-casein and (3-casein using immobilized glutamic acid-specific endopeptidase and characterization of their calcium binding. J. Dairy Sci. 81, 2858-2865. 

The matrix metalloproteinases (MMPs) are a family of calcium- and/or zinc-dependent endopeptidases involved in degradation of extracellular matrix and tissue remodelling (7). At least 21 mammalian MMPs have been described. They participate in various biological processes, such as embryonic development, ovulation, angiogenesis, apoptosis, wound heahng, and nerve growth. 

Thermolysin, a calcium-binding zinc endopeptidase consisting of 316 amino acid residues, involves a pronounced... 

Endopeptidases. At one time, venom endopeptidase was considered to be identical to pancreatic trypsin. A number of venom proteases were isolated and their specificities were investigated. Unlike trypsin, the sites of hydrolysis of venom proteases are more varied and cannot be generalized. Some venom proteases are metalloproteins that contain calcium and/or zinc ions. 

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