SEARCH · Search PubMed

Results for “TRYPSINS”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 703 records · Page 39Linked to original sources

PubMed2005

Human mesotrypsin defies natural trypsin inhibitors: from passive resistance to active destruction.

More than twenty years ago Rinderknecht et al. identified a minor trypsin isoform resistant to natural trypsin inhibitors in the human pancreatic juice. At the same time, Estell and Laskowski found that an inhibitor-resistant trypsin from the pyloric caeca of the starfish, Dermasterias imbricata rapidly hydrolyzed the reactive-site peptide bonds of trypsin inhibitors. A connection between these two seminal discoveries was made recently, when human mesotrypsin was shown to cleave the reactive-site peptide bond of the Kunitz-type soybean trypsin inhibitor, and degrade the Kazal-type pancreatic secretory trypsin inhibitor. These observations indicate that proteases specialized for the degradation of protease inhibitors are ubiquitous in metazoa, and prompt new investigations into their biological significance. Here we review the history and properties of human mesotrypsin, and discuss its function in the digestive degradation of dietary trypsin inhibitors and possible pathophysiological role in pancreatitis.

Animals↗

PubMed1983

The use of anhydrotrypsin-Sepharose for isolation of trypsin inhibitors from Vigna unguiculata seeds.

The preparation of anhydrotrypsin-Sepharose 4B for the isolation of trypsin inhibitors by affinity chromatography was described. Soybean trypsin inhibitor and an acetic acid extract of Vigna unguiculata seed meal were used to evaluate the binding of trypsin inhibitors. Both soybean trypsin inhibitor and Vigna trypsin inhibitors were retained at pH 7.6 and desorbed at pH 2.0. The Vigna trypsin inhibitors isolated by the Sepharose-4B anhydrotrypsin did not differ by SDS-polyacrylamide gel electrophoresis and isoelectric focusing from native inhibitors, indicating that partial proteolysis obtained with trypsin affinity columns can be avoided by using anhydrotrypsin, the enzymatically inactive form of the enzyme which retains the capacity to bind inhibitors.

Acetates↗

PubMed2001

Urinary trypsin inhibitor concentration can predict the immunological insult of chemotherapy and complications after bone marrow transplantation.

Urinary trypsin inhibitor has attracted attention as an index of the systemic inflammatory response syndrome. In this study, the urine concentration of trypsin inhibitor was measured to compare the immunological insult of conventional chemotherapy and conditioning chemotherapy for bone marrow transplantation. We also investigated whether urinary trypsin inhibitor was a useful index of the complications and outcome of bone marrow transplantation. Urinary trypsin inhibitor concentration was determined before chemotherapy, on the day after finishing chemotherapy (day 0 of transplantation), and during recovery of the white cell count, in 17 patients (seven receiving conventional chemotherapy and 10 receiving conditioning for bone marrow transplantation). Urinary trypsin inhibitor concentrations were significantly higher after conditioning for bone marrow transplantation than after conventional chemotherapy (P < 0.001), indicating that conditioning was more invasive. After bone marrow transplantation, the incidence of severe complications and the mortality rate were higher in patients whose urinary trypsin inhibitor concentrations rose during recovery of the white cell count. Comparison of urinary trypsin inhibitor concentrations suggested that conditioning for bone marrow transplantation was more invasive than conventional chemotherapy. This study also suggested that the urine concentration of trypsin inhibitor could be useful for predicting the risk of complications and outcome of bone marrow transplantation.

Adolescent↗

PubMed1989

Patterns of immunoreactive trypsin in serum from patients with acute abdominal disorders.

Immunoreactive trypsin in serum can be divided into trypsinogen and trypsin-alpha 1-proteinase inhibitor (alpha 1PI) complexes. These were studied separately in serum from 204 patients with acute gastro-intestinal symptoms. Elevated levels of both trypsinogen and trypsin-alpha 1PI complexes were seen in patients with acute pancreatitis. Elevated levels of trypsinogen and normal or slightly elevated levels of trypsin-alpha 1PI complexes were seen in patients with biliary tract diseases. An isolated increase in the concentration of trypsin-alpha 1PI complexes with normal trypsinogen and amylase levels were seen in patients with perforated ulcer. This third cluster may result from an absorption of active trypsin from the peritoneal cavity. Small amounts of trypsin-alpha 1PI complexes were present also in serum from patients free from pancreatic disease. The results in this study show that high levels of trypsin-alpha 1PI complexes in serum are seen mainly in patients with acute pancreatitis. However, elevated levels are also seen in other pathological conditions in the upper gastrointestinal tract; therefore an assay for these complexes is not a specific diagnostic test for acute pancreatitis.

Abdomen, Acute↗

PubMed2006

Free energy calculations show that acidic P1 variants undergo large pKa shifts upon binding to trypsin.

Serine proteinases and their protein inhibitors belong to one of the most comprehensively studied models of protein-protein interactions. It is well established that the narrow trypsin specificity is caused by the presence of a negatively charged aspartate at the specificity pocket. X-ray crystallography as well as association measurements revealed, surprisingly, that BPTI with glutamatic acid as the primary binding (P1) residue was able to bind to trypsin. Previous free energy calculations showed that there was a substantially unfavorable binding free energy associated with accommodation of ionized P1 Glu at the S1-site of trypsin. In this study, the binding of P1 Glu to trypsin has been systematically investigated in terms of the protonation states of P1 Glu and Asp189, the orientation of Gln192, as well as the possible presence of counterions using the linear interaction energy (LIE) approach and the free energy perturbation (FEP) method. Twenty-four conceivable binding arrangements were evaluated and quantitative agreement with experiments is obtained when the P1 Glu binds in its protonated from. The results suggest that P1 Glu is one of the variants of BPTI that inhibit trypsin strongest at low pH, contrary to the specificity profile of trypsin, suggesting a new regulation mechanism of trypsin-like enzymes.

Aprotinin↗

PubMed2002

Crystal structure reveals basis for the inhibitor resistance of human brain trypsin.

Severe neurodegradative brain diseases, like Alzheimer, are tightly linked with proteolytic activity in the human brain. Proteinases expressed in the brain, such as human trypsin IV, are likely to be involved in the pathomechanism of these diseases. The observation of amyloid formed in the brain of transgenic mice expressing human trypsin IV supports this hypothesis. Human trypsin IV is also resistant towards all studied naturally occurring polypeptide inhibitors. It has been postulated that the substitution of Gly193 to arginine is responsible for this inhibitor resistance. Here we report the X-ray structure of human trypsin IV in complex with the inhibitor benzamidine at 1.7 A resolution. The overall fold of human trypsin IV is similar to human trypsin I, with a root-mean square deviation of only 0.5 A for all C(alpha) positions. The crystal structure reveals the orientation of the side-chain of Arg193, which occupies an extended conformation and fills the S2' subsite. An analysis of surface electrostatic potentials shows an unusually strong clustering of positive charges around the primary specificity pocket, to which the side-chain of Arg193 also contributes. These unique features of the crystal structure provide a structural basis for the enhanced inhibitor resistance, and enhanced substrate restriction, of human trypsin IV.

Amino Acid Sequence↗

PubMed1991

Inhibitors of human and bovine trypsin and chymotrypsin in fenugreek (Trigonella foenum-graecum L.) seeds. Reaction with the human and bovine proteinases.

The reaction between the three Bowman-Birk proteinase inhibitors isolated from fenugreek seeds (TFI-B2, TFI-N2 and TFI-A8) and the human and bovine proteinases was investigated by studying the complexes formed and their properties. TFI-B2, the Lys-Leu trypsin chymotrypsin inhibitor, can bind 1.9 mol human trypsin (HT), 1.3 mol bovine trypsin (BT) and/or 0.4 mol human (HCT) or bovine (BCT) chymotrypsin per mole of inhibitor. HT was bound at the two reactive sites and BT mainly at the lysine-containing trypsin-reactive site, whereas HCT and BCT were only bound at the leucine-containing chymotrypsin-reactive site. TFI-N2, the Arg-Leu trypsin chymotrypsin inhibitor, could bind 1 mol BT and BCT, but 1.3 mol HT and 1.2 mol HCT per mole of inhibitor. In addition to the usual binding, the human enzymes could also be bound at the respective "wrong" reactive site. TFI-A8, the Arg-Arg trypsin inhibitor, binds 2 mol HT or BT per mole of inhibitor at the two trypsin-reactive sites, whereas HCT and BCT (about 0.2 mol/mol) are bound to one of the two "wrong" reactive sites.

Animals↗

PubMed1985

The specificity and kinetic properties of trypsin ethylated at the binding site.

Treatment of trypsin with triethyloxonium tetrafluoroborate at pH 8, 25 degrees C, results in abolition of binding to the enzyme of specific cationic substrates and inhibitors. The binding constant of soybean trypsin inhibitor to ethylated trypsin is 10000-fold smaller than to intact trypsin. However, the intrinsic ability of trypsin to recognize and react with nonspecific neutral substrates and inhibitors is not lost, and in several cases even considerably enhanced. Thus ethylated trypsin (Tret) resembles chymotrypsin in its behavior. Trypsin-like enzymes are also affected in a similar manner.

Binding Sites↗

PubMed1992

Differential involvement of membrane (Na-K)ATPase in thrombin- and trypsin-mediated platelet activation.

The possibility that platelet activation may also involve membrane (Na-K)ATPase was investigated by testing the effects of both proteinases on platelet shape change and aggregation in the absence and presence of the specific (Na-K)ATPase inhibitor ouabain. Ouabain (8 to 80 microM) completely antagonized trypsin-induced platelet shape change and aggregation when it was preincubated with platelet suspension before the addition of trypsin. Unlike trypsin, thrombin-induced platelet activation was significantly enhanced by ouabain. It was also observed that on partially purified beef heart (Na-K)ATPase preparation, thrombin significantly enhanced the enzyme inhibition caused by submaximal inhibitory concentrations of ouabain. Soybean trypsin inhibitor (4 micrograms/ml) employed as the agent capable to counteract proteinase effects on the (Na-K)ATPase, was shown both to prevent and antagonize the platelet activation induced by trypsin (0.3 to 1.5 micrograms/ml), but it failed to modify the responses evoked by thrombin. It is concluded that membrane (Na-K)ATPase is involved differently in platelet activation by trypsin and thrombin probably because receptor sites to which either proteinase on the platelet surface binds, are distinct. Direct enzyme involvement is indeed apparent only in trypsin-induced platelet activation.

Binding Sites↗

PubMed2005

Isolation and characterization of trypsin from pyloric caeca of Monterey sardine Sardinops sagax caerulea.

Trypsin from pyloric caeca of Monterey sardine was purified by fractionation with ammonium sulfate, gel filtration, affinity and ionic exchange chromatography. Fraction 102, obtained from ionic exchange chromatography, generated one band in sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing. The molecular mass of the isolated trypsin was 25 kDa and showed esterase-specific activity on Nalpha-p-tosyl-L-arginine methyl ester (TAME) that was 4.5 times greater than amidase-specific activity on N-benzoyl-L-arginine-p-nitroanilide. The purified enzyme was partially inhibited by the serine-protease phenyl-methyl-sulfonyl fluoride (PMSF) inhibitor and fully inhibited by the soybean trypsin inhibitor (SBTI) and benzamidine, but was not inhibited by the metallo-protease inactivator EDTA or the chymotrypsin inhibitor tosyl-L-phenylalanine chloromethyl-ketone. The optimum pH for activity was 8.0 and maximum stability was observed between pH 7 and 8. A marked loss in stability was observed below pH 4 and above pH 11. Activity was optimum at 50 degrees C and lost activity at higher temperatures. The kinetic trypsin constants K(m) and k(cat) were 0.051 mM and 2.12 s(-1), respectively, while the catalytic efficiency (k(cat)/K(m)) was 41 s(-1) mM(-1). General characteristics of the Monterey sardine trypsin resemble those of trypsins from other fish, especially trypsins from the anchovy Engraulis japonica and Engraulis encrasicholus and the sardine Sardinops melanostica.

Ammonium Sulfate↗

PubMed2003

Reconstructing the binding site of factor Xa in trypsin reveals ligand-induced structural plasticity.

In order to investigate issues of selectivity and specificity in protein-ligand interactions, we have undertaken the reconstruction of the binding pocket of human factor Xa in the structurally related rat trypsin by site-directed mutagenesis. Three sequential regions (the "99"-, the "175"- and the "190"- loops) were selected as representing the major structural differences between the ligand binding sites of the two enzymes. Wild-type rat trypsin and variants X99rT and X(99/175/190)rT were expressed in yeast, and analysed for their interaction with factor Xa and trypsin inhibitors. For most of the inhibitors studied, progressive loop replacement at the trypsin surface resulted in inhibitory profiles akin to factor Xa. Crystals of the variants were obtained in the presence of benzamidine (3), and could be soaked with the highly specific factor Xa inhibitor (1). Binding of the latter to X99rT results in a series of structural adaptations to the ligand, including the establishment of an "aromatic box" characteristic of factor Xa. In X(99/175/190)rT, introduction of the 175-loop results in a surprising re-orientation of the "intermediate helix", otherwise common to trypsin and factor Xa. The re-orientation is accompanied by an isomerisation of the Cys168-Cys182 disulphide bond, and burial of the critical Phe174 side-chain. In the presence of (1), a major re-organisation of the binding site takes place to yield a geometry identical to that of factor Xa. In all, binding of (1) to trypsin and its variants results in significant structural rearrangements, inducing a binding surface strongly reminiscent of factor Xa, against which the inhibitor was optimised. The structural data reveal a plasticity of the intermediate helix, which has been implicated in the functional cofactor dependency of many trypsin-like serine proteinases. This approach of grafting loops onto scaffolds of known related structures may serve to bridge the gap between structural genomics and drug design.

Animals↗

PubMed2002

Trypsin is produced by and activates protease-activated receptor-2 in human cancer colon cells: evidence for new autocrine loop.

In this work, we showed that human colon cancer cell lines produce trypsin which can activate a receptor for trypsin, the protease-activated receptor-2 (PAR-2), in these cells. RT-PCR experiments showed that trypsinogen transcripts were present in four colon cancer cell lines: T84, Caco-2, HT-29 and C1.19A. By Western blot analysis we found a 25 kDa immunoreactive band identified as trypsinogen I in cell lysates and in the corresponding culture media. Concentrations of trypsin in cell media were found in nanomolar range, thus compatible with activation of protease-activated receptor 2 (PAR-2). This was further demonstrated in a colon cancer cell line (H-29) Ca2+i assay since increases in Ca2+i were observed in response to media from T84, Caco-2 or C1.19A cells that were similar to that observed with 2-5 nM trypsin and were abolished by trypsin inhibitor. Altogether, these data show that colon cancer cell lines produce and secrete trypsin at concentrations compatible with activation of PAR-2. They support possible autocrine/paracrine regulation of PAR-2 activity by trypsin in colon cancer cells.

Blotting, Western↗

PubMed2003

Purification, properties and substrate specificity of a digestive trypsin from Periplaneta americana (Dictyoptera) adults.

A digestive trypsin from the American cockroach (Periplaneta americana, Dictyoptera) males was purified by a combination of anionic chromatographies in low and high pressure systems. The yield was 70% with a final specific activity of 2,000 units per mg protein (substrate: benzoyl-Arg-p-nitroanilide, BRpNA). Chemical modification with TLCK (k(obs)=3.3 M(-1) s(-1); stoichiometry 1:1) and PMSF (k(obs)=0.18 M(-1) s(-1); stoichiometry 1:1) confirmed that this peptidase is a trypsin. This enzyme has a molecular weight of 29 kDa (SDS-PAGE), a pI of 6.0 and a pH optimum of 8.9. Kinetic parameters using different colorimetric, fluorimetric and internally-quenched substrates indicated that P. americana trypsin prefers to hydrolyze synthetic substrates containing more than one amino acid residue and with an arginine residue at P1 position and a hydrophobic residue at P2. This enzyme presented a Km of 120 microM for BRpNA and is competitively inhibited by benzamidine (Ki=0.25 microM). Soybean trypsin inhibitor is a tight-binding inhibitor presenting a K(D) of 0.4 nM. Differences in substrate specificity and in the reactivity of the trypsin active site groups can be related to adaptation of insects to different hosts. P. americana trypsin is an excellent model for comparison as a basal group on evolutionary studies of insect trypsins.

Amino Acid Sequence↗

PubMed2001

Isolation and characteristics of trypsin inhibitor from the hepatopancreas of a squid (Todarodes pacificus).

Trypsin inhibitor was purified from the hepatopancreas of squid (Todarodes pacificus). The final inhibitor preparation was nearly homogeneous by SDS-PAGE with an estimated molecular weight of approximately 6300. The squid trypsin inhibitor was acid- and heat-stable, and active against trypsins from the pyloric ceca of starfish (Asterias amurensis) and saury (Cololabis saira) and porcine pancreatic trypsin. Amino acid composition of the squid trypsin inhibitor was compared with other invertebrate trypsin inhibitors. The squid trypsin inhibitor inhibited the autolysis of walleye pollock (Theragra chalcogramma) myofibrillar proteins.

Amino Acids↗

PubMed1976

Chemical-enzymatic insertion of an amino acid residue in the reactive site of soybean trypsin inhibitor (Kunitz).

Modified (Arg63-Ile64 reactive-site peptide bond hydrolyzed) soybean trypsin inhibitor (Kunitz) with all reactive amino groups, except that of Ile64, protected was described in the preceding paper (Kowalski, D., and Laskowski, M., Jr. (1976), Biochemistry, preceding paper in this issue). Treatment of this inhibitor with tert-butyloxycarbonyl-Ala- and tert-butyloxycarbonyl-Ile-N-hydroxy-succinimide esters yields inactive endo-tert-butyloxycarbonyl-Ala63A-and endo-tert-butyloxycarbonyl-Ile63A-modified inhibitors. The tert-butyloxycarbonyl groups were removed by treatment of the proteins with trifluoroacetic acid. After renaturation and purification, the resultant endo-Ala63A- and endo-Ile63A-modified inhibitors co-electrophorese with modified inhibitor both on disc gels (pH 9.4) and sodium dodecyl sulfate gels (after reduction of disulfide bonds) and show end groups corresponding to the 63A residue. These derivatives fail to form stable complexes with trypsin, extending the previous observation (Kowalski, D., and Laskowski, M., Jr. (1972), Biochemistry 11, 3451) that acylation of the P1' residue in modified inhibitors leads to inactivation. However, the incubation of endo-Ala63A- and endo-Ile63A-modified inhibitors with trypsin at pH 6.5 leads to the synthesis of the Arg63-Ala63A and Arg63-Ile63A peptide bonds in 4% yield. This is very close to the yield anticipated from a semiquantitative theory for the value of the equilibrium constant for reactive-site peptide bond. An alternative chemical method of insertion is also described. Controlled treatment of modified inhibitor with the N-carboxyanhydride of Glu produced inactive endo-Glu63A-modified inhibitor. Incubation of this inactive derivative with trypsin at pH 6.5 leads to 16% synthesis of the Arg63-Glu63A peptide bond. The higher yield of single chain protein in this case is attributed to the influence of the negative charge of the Glu63A side chain. Thus, the insertion of an amino acid residue between the P1 and P1' residues in soybean trypsin inhibitor (Kunitz) converts a trypsin inhibitor into a trypsin substrate.

Amino Acid Sequence↗

PubMed2001

A Kunitz trypsin inhibitor gene family from trembling aspen (Populus tremuloides Michx.): cloning, functional expression, and induction by wounding and herbivory.

Three Kunitz trypsin inhibitor genes were isolated from trembling aspen (Populus tremuloides) by PCR and cDNA screening. Based on sequence similarity, they were grouped into two classes. Southern blots showed complex banding patterns and a high level of restriction fragment polymorphism between different aspen genotypes, suggesting that these trypsin inhibitors are members of a large, rapidly evolving gene family. One of the trypsin inhibitor genes, PtTI2. was over-expressed in Escherichia coli and its product shown to inhibit bovine trypsin in vitro. Both classes of PtTI genes are induced by wounding and herbivory, permitting rapid adaptive responses to herbivore pressure. The response appears to be mediated by an octadecanoid-based signaling pathway, as methyl jasmonate treatments induced the trypsin inhibitors. Wound-induced accumulation of trypsin inhibitor protein was also observed by western blot analysis. The pattern of expression, the apparent rapid evolution of TI genes, and the in vitro trypsin inhibitory activity are consistent with a role in herbivore defense. This work establishes the presence of a functional protein-based inducible defense system in trembling aspen.

Acetates↗

PubMed2003

Human mesotrypsin is a unique digestive protease specialized for the degradation of trypsin inhibitors.

Mesotrypsin is an enigmatic minor human trypsin isoform, which has been recognized for its peculiar resistance to natural trypsin inhibitors such as soybean trypsin inhibitor (SBTI) or human pancreatic secretory trypsin inhibitor (SPINK1). In search of a biological function, two conflicting theories proposed that due to its inhibitor-resistant activity mesotrypsin could prematurely activate or degrade pancreatic zymogens and thus play a pathogenic or protective role in human pancreatitis. In the present study we ruled out both theories by demonstrating that mesotrypsin was grossly defective not only in inhibitor binding, but also in the activation or degradation of pancreatic zymogens. We found that the restricted ability of mesotrypsin to bind inhibitors or to hydrolyze protein substrates was solely due to a single evolutionary mutation, which changed the serine-protease signature glycine 198 residue to arginine. Remarkably, the same mutation endowed mesotrypsin with a novel and unique function: mesotrypsin rapidly hydrolyzed the reactive-site peptide bond of the Kunitz-type trypsin inhibitor SBTI, and irreversibly degraded the Kazal-type temporary inhibitor SPINK1. The observations suggest that the biological function of human mesotrypsin is digestive degradation of trypsin inhibitors. This mechanism can facilitate the digestion of foods rich in natural trypsin inhibitors. Furthermore, the findings raise the possibility that inappropriate activation of mesotrypsinogen in the pancreas might lower protective SPINK1 levels and contribute to the development of human pancreatitis. In this regard, it is noteworthy that the well known pathological trypsinogen activator cathepsin B exhibited a preference for the activation of mesotrypsinogen of all three human trypsinogen isoforms, suggesting a biochemical mechanism for mesotrypsinogen activation in pancreatic acinar cells.

Catalysis↗

PubMed2000

Biochemical evidence of specific trypsin-chymotrypsin inhibitors in the rhynchobdellid leech, Theromyzon tessulatum.

The presence of two specific trypsin-chymotrypsin inhibitors from head parts of the rhynchobdellid leech Theromyzon tessulatum is reported. Two proteins, anti-trypsin chymotrypsin A (ATCA; 14636.6 +/- 131 Da) and anti-trypsin-chymotrypsin B (ATCB; 14368 +/- 95 Da) were purified by size exclusion and anion-exchange chromatography followed by reversed-phase HPLC. Based on amino-acid composition, N-terminal sequence determination (MELCELGQSCSRD-NPQPSNM), matrix assisted laser desorption-time of flight measurement (MALDI-TOF), trypsin mapping comparison, inhibition constant determination (Ki), and influence on amidolytic activity of different serine proteases, it is demonstrated that ATCA and ATCB are novel and highly potent serine-protease inhibitors of trypsin and chymotrypsin (ATCA: 350fM towards trypsin and chymotrypsin; ATCB: 400 and 75 fM towards trypsin and chymotrypsin, respectively). It is further surmised that ATCA and ATCB are linked, in that ATCB would lead to the formation of ATCA after loss of few amino acid residues.

Amino Acid Sequence↗