There are four commercial sources of trypsin inhibitors.
|Source||Molecular weight||Inhibitory power||Details|
|Serum (α1-antitrypsin)||52 kDa||Also known as serum trypsin inhibitor|
|Lima beans||8-10 kDa||2.2 times weight||There are six different lima bean inhibitors.|
|Bovine pancreas||6.5 kDa||2.5 times weight||Kunitz inhibitor, or BPTI (basic pancreatic trypsin inhibitor, is the best-known pancreatic inhibitor. Chymotrypsin is also inhibited by this chemical, but less tightly. When extracted from lung tissue, this is known as aprotinin.|
|Ovomucoid||8-10 kDa||1.2 times weight||Ovomucoids are the glycoprotein protease inhibitors found in raw avian egg white. There are other protease inhibitors in ovomucoids as well.|
|Soybeans||20.7-22.3 kDa||1.2 times weight||Soybeans contain several inhibitors; the one in the chart is considered the primary one. All of them bind chymotrypsin to a lesser degree.|
A study revealing that protease inhibitor from the eggs of the freshwater snail Pomacea canaliculata, interacting as a trypsin inhibitor with the protease of potential predators, was reported in 2010, the first direct evidence for this mechanism in the animal kingdom.
Tumor-Associated Trypsin Inhibitor (TATI) has been used as a marker of mucinous ovarian carcinoma, urothelial carcinoma, and renal cell carcinoma. TATI is metabolised by the kidneys and is, thus, elevated in patients with renal failure. It may be elevated in nonneoplastic processes such as pancreatitis and can be used as a prognostic marker in this setting (levels above 70 micrograms/L are associated with poor prognosis).
Fifty percent of stage I mucinous ovarian carcinomas are associated with elevated TATI, and nearly 100% of stage IV tumors show elevated TATI.
Eighty-five to 95% of pancreatic adenocarcinomas are associated with increased TATI (but elevation in pancreatitis limits the clinical utility of TATI in this setting; see above).
Sixty percent of gastric adenocarcinomas show elevated TATI, in particular tumors of diffusely infiltrative/signet ring type. TATI, thus, complements CEA, which is elevated exclusively in intestinal type adenocarcinoma of the stomach.
In urothelial carcinoma, TATI expression varies with stage, ranging from 20% in low-stage tumors to 80% of high-stage tumors.
TATI sensitivity in the setting of renal cell carcinoma is approximately 70%. Elevated TATI is more likely to be see in patients with advanced-stage disease.
In nearly all tumor types studied, TATI is a marker of poor prognosis.
According to the article "Association of tumor-associated trypsin inhibitor (TATI) expression with molecular markers, pathologic features and clinical outcomes of urothelial carcinoma of the urinary bladder" many of the statements made above are not true. These researchers found that low TATI is an indication of higher lethality and recurrence rates for bladder cancer. 100% of healthy cells do express high levels of TATI.
- Dreon M. S., Ituarte S. & Heras H. (2010). "The Role of the Proteinase Inhibitor Ovorubin in Apple Snail Eggs Resembles Plant Embryo Defense against Predation". PLoS ONE 5(12): e15059. doi:10.1371/journal.pone.0015059.
- De Mais, Daniel. ASCP Quick Compendium of Clinical Pathology, 2nd Ed. ASCP Press 2009.
||This article includes a list of references, but its sources remain unclear because it has insufficient inline citations. (December 2010)|
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