Editing Protease (section)

==Inhibitors==
{{main|Protease inhibitor (biology)|Protease inhibitor (pharmacology)}}
The activity of proteases is inhibited by [[protease inhibitor (biology)|protease inhibitor]]s.<ref>{{cite journal | vauthors = Southan C | title = A genomic perspective on human proteases as drug targets | journal = Drug Discovery Today | volume = 6 | issue = 13 | pages = 681–688 | date = July 2001 | pmid = 11427378 | doi = 10.1016/s1359-6446(01)01793-7 }}</ref> One example of protease inhibitors is the [[serpin]] superfamily. It includes [[alpha 1-antitrypsin]] (which protects the body from excessive effects of its own [[inflammation|inflammatory]] proteases), [[alpha 1-antichymotrypsin]] (which does likewise), [[C1-inhibitor]] (which protects the body from excessive protease-triggered activation of its own [[complement system]]), [[antithrombin]] (which protects the body from excessive [[coagulation]]), [[plasminogen activator inhibitor 1|plasminogen activator inhibitor-1]] (which protects the body from inadequate coagulation by blocking protease-triggered [[fibrinolysis]]), and [[neuroserpin]].<ref>{{cite journal | vauthors = Puente XS, López-Otín C | title = A genomic analysis of rat proteases and protease inhibitors | journal = Genome Research | volume = 14 | issue = 4 | pages = 609–622 | date = April 2004 | pmid = 15060002 | pmc = 383305 | doi = 10.1101/gr.1946304 }}</ref>

Natural protease inhibitors include the family of [[lipocalin]] proteins, which play a role in cell regulation and differentiation. [[Lipophilic]] ligands, attached to lipocalin proteins, have been found to possess tumor protease inhibiting properties. The natural [[protease inhibitor (biology)|protease inhibitor]]s are not to be confused with the [[protease inhibitor (pharmacology)|protease inhibitor]]s used in antiretroviral therapy. Some [[virus (biology)|virus]]es, with [[HIV/AIDS]] among them, depend on proteases in their reproductive cycle. Thus, [[protease inhibitor (pharmacology)|protease inhibitor]]s are developed as [[Antiviral drug|antiviral]] therapeutic agents.

Other natural protease inhibitors are used as defense mechanisms. Common examples are the [[trypsin inhibitor]]s found in the seeds of some plants, most notable for humans being soybeans, a major food crop, where they act to discourage predators. Raw soybeans are [[Soybean#Nutrition|toxic]] to many animals, including humans, until the protease inhibitors they contain have been denatured.