Plasma trypsin inhibitor

Soy protein preparations contain a variety of biologically active compounds including saponins, fibers, trypsin inhibitors, and isoflavones (Potter, 2000). Hamsters and rats fed ethanol-extracted soy protein isolates had no ability to lower plasma cholesterol compared to intact soy protein isolates (Lucas et al., 2001 Ni et al., 1999). Extraction with ethanol is a treatment that would remove saponins, isoflavones, and other phytochemicals from the protein. Although one study showed that ethanol washing did not... 

Human pancreatic secretory trypsin inhibitor (hPSTI) can be potentially assayed as an indicator of necrotic complications in AP (Ol). This protein is an inhibitor of trypsinogen, which is produced in acinar cells in the quantity of approximately 2% of the potential content of trypsin in pancreas. Trypsin binds with its inhibitor hPSTI, then with AMG, and only this complex, trypsin-o 2-macroglobulin, is eliminated from plasma (B10). Pezzili (P3) suggests that early attempts to determine the severity of the AP process based on the measurement of hPSTI within 24 hr from the first sensations of pain show a sensitivity of 79%, whereas an increase in CRP concentration has a sensitivity of 29% only (Table 3). 

Hyaluronan also occurs covalently bound to proteins such as inter-alpha trypsin inhibitor, a plasma protein that also functions as a stabilizer of HA-rich structures,21,22 such as the cumulus mass surrounding the mammalian ovum.23... 

The plasma peptide component from 10 melanoma and healthy individuals was examined by a combination of RP-HPLC, SEEDI-TOF-MS, and tandem MS. Fibrinogen a and inter-a-trypsin inhibitor heavy chain H4 fragments were absent in tumor samples [106]. 

For enzyme inhibition assays, urine is the preferred specimen [4]. Interestingly, Bik can be measured by the inhibition of trypsin in urine but not in plasma. Urinary Bik analysis may also be performed by antibody staining, latex agglutination, and radioimmunoassay (RIA) [4]. Despite the analytical approach used, all Bik forms are measured together. The enzyme inhibition method involves adding known amounts of trypsin to the specimen and monitoring trypsin inhibition. Trypsin activity is assessed by detection of by-products from a cleavable substrate. Dipstick methods are available for the rapid detection of trypsin inhibitors in urine [15, 17 19]. 

Morishita H, Yamakawa T, Matsusue T, Kusuyama T, Sameshima-Aruga R, Hirose J, et al. Novel factor Xa and plasma kallikrein inhibitory activities of the second Kunitz-type inhibitory domain of urinary trypsin inhibitor. Thromb Res 1994 73 193-204. 

Masuda J, Suzuki K, Satoh A, Kojima-Aikawa K, Nakanishi K, Kuroda K, et al. Matsumoto I. Beta-2-glycoprotein I and urinary trypsin inhibitor levels in the plasma of pregnant and postpartum women. Thromb Res 2006 117 255-261. 

A number of protease inhibitors are being used currently for treating disease. Trasylol [Bayer s trademark for pancreatic trypsin inhibitor (Kunitz)] is being used currently in Europe for treating pancreatitis. This disease, which is often fatal in young alcoholic men and older women, results in the leakage of pancreatic proteases into the plasma. 

Plasma premixed 1 1 with soybean trypsin inhibitor (2 mg/ml VS). 

G proteins are located in different compartments within the cell (Nurnberg and Ahnert-Hilger, 1996). Although most G proteins are found attached to the plasma membrane and intracellular membranes, some are also located within the cytoplasm (Rudolph et al., 1989). Therefore, G proteins in preparations of disrupted cells, or in cell and tissue extracts are also subject to pertussis toxin-mediated ADP-ribosylation. In this case, precautions have to be taken to prevent proteolysis, and protease inhibitors should be included in the buffer (aprotonin, p-aminobenzamidine, leupeptin, phenylmethylsul-fonyl fluoride, or soybean or lima bean trypsin inhibitors) (Carty, 1994). 

The major plasma inhibitor of Factor XIa is Uj-antitrypsin while antithrombin III, in the presence or absence of heparin, plays a minor role in controlling this enzyme (S5). Interestingly, plant inhibitors like soybean, com, and lima bean trypsin inhibitors are able to block Factor Xlla and kallikrein but only mildly inhibit Factor XI. Thus, one can use these agents to minimize cross-reactivity in an indirect s)mthetic substrate assay for Factor XIa. 

Aprotinin - which is also known as bovine pancreatic trypsin inhibitor (BPTI) - belongs to the family of Kunitz-type inhibitors, and inhibits serine proteases such as trypsin, chymotrypsin, plasmin, and plasma kaUikrein [15]. Aprotinin consists of 58 amino acids. The aprotinin variant (DesPro(2)-Ser(10)-Arg(15)-Ala(17)-Asp(24)-Thr(26)-Glu(31)-Asn(41)-Glu(53)-aprotinin) was designed by means of rational mutagenesis, and differs from aprotinin by two amino acids in the active site and by seven amino acids in the backbone. The changes in the active site of the aprotinin variant increase the potency towards inhibition of plasma kaUikrein, whereas the inhibition of plasmin is only marginally reduced. 

It has been demonstrated that a factor capable of increasing vascular permeability is formed when plasma of certain species is diluted with saline in contact with glass. The activity is associated with a globulin, the particular fraction varying from species to species. An inhibitor also occurs in plasma. Activation by dilution is attributed to the splitting of a P.F.-precursor/P.F.-inhibitor complex. As it is inhibited by the various known trypsin inhibitors and by dyflos (D.F.P., isoflurophate), Miles considered that globulin P.F. may be a protease, but no substrate has been demonstrated. Globulin P.F. may, in fact, be identical with kallikrein. 

Human plasma Uj -Trypsin inhibitor 54,000 Trypsin, chymotrypsin, elastase, plasmin 11 ... 

Interesting is the problem of trypsin and its inhibitor. The normal concentration of trypsin in plasma (211), 0.2 ng/l ml, is not apprehensible by polarography. Trypsin, however, can be added to the serum in a standard quantity, and the decrease in the activity in this serum can be compared with the activity in another serum in which the trypsin inhibitor has been inactivated by heating (30 min at 60°C). 

On considering that liberation of the C-kinin in the serum of HANE patients was blocked by soybean trypsin inhibitor and EACA, compounds which do not inhibit Cls, another plasma protease, such as plasma kal-likrein or plasmin, appeared to be involved in the liberation of the C-kinin (Nilsson et al., 1966 Lundh et aL, 1968 Sheffer et al., 1972). Furthermore, the disease responds to treatment with the plasmin inhibitors trasylol and EACA (Sheffer et al., 1972 Frank et al., 1972). 

XI Plasma thromboplastin antecedent M, 124000 (bovine), 160000 (human). Glycoprotein composed of 2 similar or identical polypeptides joined by disulfide bond(s). Activates IX.IXa is inhibited by antithrombin III, trypsin inhibitors, a,-trypsin inhibitor and Cl inhibitor. 

Khayambashi, H., and Lyman, R. L., 1969, Secretion of rat pancreas perfused with plasma from rats fed soybean trypsin inhibitor. Am. J. Physiol., 217 646-651. 

As a further control, the Enzite-trypsin was incubated with soybean trypsin inhibitor (SBTI) prior to incubation with plasma. 

Figure 4. Renin concentration after 24 hr preincubation of plasma with trypsin (T) or trypsin and soybean trypsin inhibitor (SBTI). X—X plasma incubated without trypsin.

The plasma or serum of mammals is able to inhibit all kallikreins. This inhibition appears to be reversible. The acidification of an inactive mixture of kallikrein and plasma results in the reappearance of kininogenase activity. In addition, diiso-propylphosphorofluoridate (DFP), soya-bean trypsin inhibitor, potato trypsin inhibitor, some ester substrates of kallikrein and other substances have been shown to decrease the activity of one or several kininogenases. 

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