Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.21.4 (trypsin)
 42,187 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Pancreatic juice is naturally supersaturated in calcium and bicarbonate ions. A mechanism controlling CaCO3 crystal formation and growth is therefore necessary to prevent duct clogging. The present study shows that lithostathine, a glycoprotein present in human pancreatic juice at a concentration in the range of 10 mumol/L, could be involved in such a control. Lithostathine in concentrations greater than 1.5 mumol/L significantly delayed crystal nucleation and inhibited growth of preformed CaCO3 crystals from supersaturated solutions. Adsorption of lithostathine on crystals was shown by immunodetection. Albumin also adsorbed on CaCO3 crystals, but neither albumin nor other pancreatic secretory proteins inhibited crystal nucleation or growth. Lithostathine adsorbed to sites specifically inhibiting crystal growth with a dissociation constant (Kd) = 0.9 x 10(-6) mol/L. The glycosylated amino-terminal undecapeptide generated by limited trypsin hydrolysis inhibited CaCO3 crystal growth with a Kd = 3.0 x 10(-6) mol/L, similar to that of lithostathine. On the contrary, the carboxy-terminal polypeptide was inactive. A synthetic undecapeptide identical to the N-terminal end but not glycosylated was equally active. The activity disappeared upon digestion of the undecapeptide with V8 protease. The N-terminal undecapeptide of lithostathine is therefore essential to the inhibitory activity of the protein on CaCO3 crystal growth.
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PMID:Inhibition of nucleation and crystal growth of calcium carbonate by human lithostathine. 139 86

Pancreatic stones of patients with chronic calcifying pancreatitis (CCP) are mostly made up of CaCO3 crystals. Formation and growth of such crystals is inhibited in vitro by lithostathine, a protein present in normal pancreatic juice. Decreased lithostathine activity was therefore suspected in patients with CCP, but comparison by immunoassay of lithostathine concentrations in the pancreatic juices of patients and controls led to conflicting results. This study shows that these discrepancies might have been caused in part by a remarkably high susceptibility of the protein to trypsin like cleavage, resulting in important structural changes and concomitant modifications of the epitopes. A novel lithostathine assay in juice was developed, based on separation of secretory proteins by high performance liquid chromatography. The chromatographic separation of lithostathine was based on hydrophobic interactions at pH 5.0 using a Phenyl-TSK column. This study showed with this assay that lithostathine concentrations (microgram/mg of total protein) were similar in CCP patients with alcoholic aetiology (mean (SD) 6.3 (2.7)) and other aetiologies (7.2 (3.7)), but one third of those estimated in patients without pancreatic disease (16.7 (4.3)). Similar concentrations were found, however, in chronic alcoholic patients without CCP (6.6 (3.3)) and in patients with CCP. It was concluded that decreased lithostathine concentration is associated with CCP, although such a decrease is not sufficient by itself for the disease to occur.
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PMID:Quantification of human lithostathine by high performance liquid chromatography. 773 75

Pancreatic juice is naturally supersatured in calcium and bicarbonate ions. A mechanism controlling CaCO3 crystal formation and growth is therefore necessary to prevent duct clogging. Lithostathine, a glycoprotein synthesized by acinar cells and secreted in pancreatic juice, could be involved in such a control. Lithostathine significantly delayed crystal nucleation and inhibited growth of CaCO3 crystals from supersatured solutions. Lithostathine adsorbed to sites specifically inhibiting crystal growth with a dissociation constant Kd = 0.9 x 10(-6) mol/L. The glycosylated N-terminal undecapeptide generated by limited trypsin hydrolysis of lithostathine, inhibited CaCO3 crystal growth with a Kd = 3.4 x 10(-6) mol/L similar to that of lithostathine. On the contrary, the carboxy-terminal polypeptide (lithostathine H) was inactive. The N-terminal undecapeptide of lithostathine is therefore essential to the inhibitory activity of the protein on CaCO3 crystal growth.
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PMID:[Pancreatic lithostathine inhibitor of calcium carbonate precipitation: structure-function relationship]. 814 82

Apart from digestive enzymes, pancreatic juice contains several proteins that are not directly involved in digestion. One of these, lithostathine, has been reported to exhibit calcite crystal inhibitor activity in vitro. As pancreatic juice is supersaturated with respect to calcium carbonate, it was hypothesized that lithostathine stabilizes pancreatic juice. Lithostathine is cleaved by trace amounts of trypsin, resulting in a C-terminal polypeptide and an N-terminal undecapeptide, which has been identified as the active site of lithostathine regarding crystal inhibition. We produced rat lithostathine in a baculovirus expression system. In order to test its functional activity, the protein was purified using a nondenaturing multi-step procedure. In the low micromolar range, recombinant rat lithostathine in vitro exhibited calcite crystal inhibitor activity, confirming earlier reports. Limited tryptic proteolysis of recombinant lithostathine was performed, and the two cleavage products were separated; the C-terminal polypeptide was precipitated by centrifugation, and the N-terminal undecapeptide was purified by high performance liquid chromatography. Only the C-terminal peptide displayed measurable calcite crystal inhibitory activity. Furthermore, synthetic undecapeptides with identical sequence to the N-terminal undecapeptides of rat or human lithostathine were inactive. However, when tested in the same in vitro assays, other pancreatic or extra-pancreatic proteins show inhibitory activity in the same concentration range as lithostathine, and inorganic phosphate is active as well. Based on these findings it seems unlikely that lithostathine is a physiologically relevant calcite crystal inhibitor. The name "lithostathine" is therefore inappropriate, and the protein's key function remains to be elucidated.
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PMID:Pancreatic stone protein (lithostathine), a physiologically relevant pancreatic calcium carbonate crystal inhibitor? 900 58

Reg protein was first found in pancreatic stones. It was named Pancreatic Stone Protein and later renamed lithostathine, as it was assumed to prevent stone formation. The 144 amino acid protein is O-glycosylated on Thr-5. The glycan chain is variable in length and in charge. Lithostathine 3-D organization is of the C-lectin type, even though it is unlikely to have any functional calcium-binding site. The Arg11-Ile12 bond is readily cleaved by trypsin; the resulting C-terminal polypeptide precipitates at physiological pH and tends to form fibrils. The protein was more recently found in the regenerating endocrine pancreas and it was named Reg (for regenerating) protein. Numerous proteins related to Reg have been identified successively in several mammalian species. They constitute the Reg superfamily. Reg genes show the same organization and are located in the same chromosome region. These genes are therefore likely to derive from a common ancestor gene by duplication. In the course of evolution, they may have diverged in tissue-related expression and function. In the endocrine pancreas, Reg protein stimulates islet beta-cell growth and reduces experimental diabetes via the activation of a high affinity receptor. The role of the protein produced by the exocrine pancreas, however, is controversial. Not only is Reg/lithostathine unlikely to be a physiologically relevant pancreatic stone inhibitor, but it may contribute to stone formation. We suggest that it might help prevent the harmful activation of protease precursors in the pancreatic juice. The protein provides a useful model for examining the conformational changes associated with globular to fibril transformation.
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PMID:Protein-X, Pancreatic Stone-, Pancreatic thread-, reg-protein, P19, lithostathine, and now what? Characterization, structural analysis and putative function(s) of the major non-enzymatic protein of pancreatic secretions. 1236 99

Continuous modes of renal replacement therapy (CRRT) are increasingly being utilized in the intensive care unit. The removal of cytokines and other inflammatory proteins during ultrafiltration may be responsible for some of the beneficial effects of CRRT. We used proteomic tools to identify proteins found in the ultrafiltrate from a patient with acute renal failure. Identification of these proteins could help elucidate the mechanism(s) of improved outcome with continuous renal replacement therapy. Protein was loaded on a reversed-phase C4 column and eluted with stepwise isocratic flows starting with 0%, 5%, 10%, 25%, and 50% of acetonitrile. Effluent was collected, pooled, desalted, and separated by two-dimensional gel electrophoresis (2DE). Reversed-phase separation improved the resolution and the number of spots seen on the gels. Protein spots were digested with trypsin and spotted onto MALDI plates. Proteins were identified by either peptide mass fingerprinting using a MALDI-TOF mass spectrometer or by peptide sequencing using a MALDI-TOF/TOF tandem mass spectrometer. From 196 spots cut, 47 were identified, representing multiple charge forms of 10 different proteins. Proteins identified were albumin, apolipoprotein A-IV, beta-2-microglobulin, lithostathine, mannose-binding lectin associated serine protease 2 associated protein, plasma retinol-binding protein, transferrin, transthyretin, vitamin D-binding protein and Zn alpha-2 glycoprotein. Continuous renal replacement therapy is frequently used in acutely ill patients with renal failure. Removal of proteins occurs during this process. The physiological significance of this protein removal is unclear. Identification of these proteins will lead to better understanding of the role of protein removal in continuous renal replacement therapy.
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PMID:Identification of proteins in slow continuous ultrafiltrate by reversed-phase chromatography and proteomics. 1559 35

Symptoms of choledochal cysts are caused by protein plugs. We performed proteomic analysis of protein plugs to elucidate formation mechanism. Protein plugs were obtained from three pediatric patients with choledochal cyst. Proteins were separated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Gel bands common to the samples were excised for mass spectrometry. Mass spectra were compared with the NCBI database for protein identification. Gel bands of protein plug samples were predominant at 14 kilodaltons (kDa), followed by 29 kDa. Four other thin bands were common to the plug samples. Four bands (including 14 and 29 kDa) were identified as lithostathine, and one band as serum albumin. Plugs consisted mostly of lithostathine, a protein secreted by pancreatic acinar cells into pancreatic juice. The mechanism involves trypsinogen and lithostathine regurgitating into the cyst through an aberrant union of pancreaticobiliary ducts. Activated trypsin cleaves soluble lithostathine into insoluble forms that aggregate to form plugs.
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PMID:Proteomic analysis of protein plugs: causative agent of symptoms in patients with choledochal cyst. 1741 47

Pancreatic stone protein (PSP; reported in 1979), pancreatitis-associated protein (PAP; 1984) and regenerating protein (Reg I; 1988) were discovered independently in the fields of the exocrine (pancreatitis) and endocrine (diabetes) pancreas. Subsequent analysis revealed that PSP and Reg I are identical and PAP belongs to the same protein family. PSP/Reg I and PAP share a selective and specific trypsin cleavage site and result in insoluble fibrils (PTP, PATP). Search for a functional role of PSP had led to the idea that it might serve as an inhibitor in pancreatic stone formation and PSP was renamed lithostathine. Inhibitory effects of lithostathine in stone formation have been questioned. Evidence so far obtained can support a lithogenic role rather than a lithostatic role of PSP. PAP and its isoforms have been investigated mainly regarding responses to inflammation and stress. Reg I and its isoforms have been examined on regeneration, growth and mitogenesis in gastrointestinal neoplastic diseases as well as diabetes. Evidence obtained can be applied in the prediction of prognosis and therapy for inflammatory and neoplastic diseases.
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PMID:Pancreatic stone protein/regenerating protein family in pancreatic and gastrointestinal diseases. 2180 74