The heavy chain of coagulation factor VII contains a serine esterase entity. A partial cleavage in the heavy chain occurs during purification and activation of the single-chain zymogen, presumably as a result of autolysis. Neutrophil cathepsin G initially generates a Gla-domainless FVIIa without coagulant activity. However, on extended exposure cleavage also occurs in the heavy chain, resulting in a complete loss of enzyme activity. Four cleavage sites on the heavy chain, two susceptible to trypsin-like autolysis and two susceptible to chymotrypsin-like cathepsin G-mediated catalysis have been identified. The hydrolysis of peptide bonds in the heavy chain might contribute to regulation of the coagulation process in vivo. © 1993.
Nicolaisen, E. M., Thim, L., Jacobsen, J. K., Nielsen, P. F., Mollerup, I., Jørgensen, T., & Hedner, U. (1993). FVIIa derivatives obtained by autolytic and controlled cathepsin G mediated cleavage. FEBS Letters, 317(3), 245–249. https://doi.org/10.1016/0014-5793(93)81285-8