Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Chronic pancreatitis (CP) is a continuing or relapsing inflammatory disease of the pancreas. In approximately one-third of all cases, no aetiological factor can be found, and these patients are classified as having idiopathic disease. Pathophysiologically, autodigestion and inflammation may be caused by either increased proteolytic activity or decreased protease inhibition. Several studies have demonstrated mutations in the cationic trypsinogen gene (PRSS1) in patients with hereditary or idiopathic CP. It is thought that these mutations result in increased trypsin activity within the pancreatic parenchyma. Most patients with idiopathic or hereditary CP, however, do not have mutations in PRSS1 (ref. 4). Here we analysed 96 unrelated children and adolescents with CP for mutations in the gene encoding the serine protease inhibitor, Kazal type 1 (SPINK1), a pancreatic trypsin inhibitor. We found mutations in 23% of the patients. In 18 patients, 6 of whom were homozygous, we detected a missense mutation of codon 34 (N34S). We also found four other sequence variants. Our results indicate that mutations in SPINK1 are associated with chronic pancreatitis.
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PMID:Mutations in the gene encoding the serine protease inhibitor, Kazal type 1 are associated with chronic pancreatitis. 1083 40

For decades there has been slow progress in understanding pancreatic diseases, particularly acute and chronic pancreatitis. As a result, there were no significant advances in the management of these patients. Treatment was mostly directed towards symptomatic relief and management of complications. A simple clinical observation that multiple members of a large family are affected by acute and chronic pancreatitis, some at very young age and in the absence of any alcohol use, led physician-scientists of the Midwest Multicenter Pancreatic Study Group (investigators from the University of Cincinnati, University of Kentucky, and University of Pittsburgh) to investigate the genetic basis of hereditary pancreatitis. Using information from the human genome project, the hereditary pancreatitis gene was identified as the cationic trypsinogen gene (protease serine 1, PRSS1). This discovery has led to the identification of a number of other genes and their products playing role in the pathogenesis of acute and chronic pancreatitis. In the emerging picture of pathogenesis of acute and chronic pancreatitis, trypsin appears to play a central role. This newly acquired knowledge is setting the stage for new preventive and management strategies for hereditary and sporadic acute and chronic pancreatitis.
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PMID:Lessons from hereditary pancreatitis. 1147 Dec 4

Since the identification in 1996 of a "gain of function" missense mutation, R122H, in the cationic trypsinogen gene (PRSS1) as a cause of hereditary pancreatitis, continued screening of this gene in both hereditary and sporadic pancreatitis has found more disease-associated missense mutations than expected. In addition, functional analysis has yielded interesting findings regarding their underlying mechanisms resulting in a gain of trypsin. A critical review of these data, in the context of the complicated biogenesis and complex autoactivation and autolysis of trypsin(ogen), highlights that PRSS1 mutations cause the disease by various mechanisms depending on which biochemical process they affect. The discovery of these mutations also modifies the classical perception of the disease and, more importantly, reveals fascinating new aspects of the molecular evolution and normal physiology of trypsinogen. First, activation peptide of trypsinogen is under strong selection pressure to minimize autoactivation in higher vertebrates. Second, the R122 primary autolysis site has further evolved in mammalian trypsinogens. Third, evolutionary divergence from threonine to asparagine at residue 29 in human cationic trypsinogen provides additional advantage. Accordingly, we tentatively assign, in human cationic trypsinogen, the strongly selected activation peptide as the first-line and the R122 autolysis site as the second-line of the built-in defensive mechanisms against premature trypsin activation within the pancreas, respectively, and the positively selected asparagine at residue 29 as an "amplifier" to the R122 "fail-safe" mechanism.
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PMID:Molecular pathology and evolutionary and physiological implications of pancreatitis-associated cationic trypsinogen mutations. 1170 3

Hereditary pancreatitis has been found to be associated with germline mutations in the cationic trypsinogen (PRSS1) gene. Here we report a family with hereditary pancreatitis that carries a novel PRSS1 mutation (R122C). This mutation cannot be diagnosed with the conventional screening method using AflIII restriction enzyme digest. We therefore propose a new assay based on restriction enzyme digest with BstUI, a technique that permits detection of the novel R122C mutation in addition to the most common R122H mutation, and even in the presence of a recently reported neutral polymorphism that prevents its detection by the AflIII method. Recombinantly expressed R122C mutant human trypsinogen was found to undergo greatly reduced autoactivation and cathepsin B-induced activation, which is most likely caused by misfolding or disulfide mismatches of the mutant zymogen. The K(m) of R122C trypsin was found to be unchanged, but its k(cat) was reduced to 37% of the wild type. After correction for enterokinase activatable activity, and specifically in the absence of calcium, the R122C mutant was more resistant to autolysis than the wild type and autoactivated more rapidly at pH 8. Molecular modeling of the R122C mutant trypsin predicted an unimpaired active site but an altered stability of the calcium binding loop. This previously unknown trypsinogen mutation is associated with hereditary pancreatitis, requires a novel diagnostic screening method, and, for the first time, raises the question whether a gain or a loss of trypsin function participates in the onset of pancreatitis.
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PMID:Hereditary pancreatitis caused by a novel PRSS1 mutation (Arg-122 --> Cys) that alters autoactivation and autodegradation of cationic trypsinogen. 1171 9

The recent genetic discoveries in CP support the hypothesis that inappropriate intrapancreatic activation of zymogens by trypsin results in autodigestion and pancreatitis. Two different protective mechanisms prevent activation of the pancreatic digestive enzyme cascade. First, SPINK1 inhibits up to 20% of potential trypsin activity and, second, trypsin itself activates trypsin-like enzymes readily degrading trypsinogen and other zymogens. Pancreatitis may therefore be the result of an imbalance between proteases and their inhibitors within the pancreatic parenchyma. The discovery of PRSS1 mutations in families with CP was the first breakthrough in the understanding of the underlying genetic mechanisms. Enhanced trypsinogen activation may be the common initiating step in pancreatitis caused by these mutations. The discovery of SPINK1 mutations underlines the importance of the protease inhibitor system in the pathogenesis of CP. Thus, gain-of-function in the cationic trypsinogen resulting in an enhanced autoactivation, or loss-of-function mutations in SPINK1 leading to decreased inhibitory capacity, may similarly disturb the delicate intrapancreatic balance of proteases and their inhibitors. The recent findings of SPINK1, CFTR, and PRSS1 mutations in CP patients without a family history have challenged the concept of idiopathic CP as a non-genetic disorder and the differentiation between HP and ICP. There is a clear mode of autosomal dominant inheritance for some mutations (R122H, N291, possibly MIT), whereas the inheritance pattern (autosomal recessive, complex, or modifying) of other mutations (A16V, N34S) is controverted or unknown. The lack of mutations in the above-mentioned genes in many patients suggests that CP may also be caused by genetic alterations in yet unidentified genes. Evaluation of CP patients without an obvious predisposing factor, e.g. alcohol abuse, should include genetic testing even in the absence of a family history of pancreatitis. Finally, identification of further disease-causing genes will create a better understanding of pathogenesis and may help to develop specific preventive and therapeutic strategies.
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PMID:Genetic aspects of chronic pancreatitis: insights into aetiopathogenesis and clinical implications. 1177 91

Hereditary pancreatitis (HP) is usually caused by mutations in the cationic trypsinogen (PRSS1) gene, especially R122H or N29I. We sequenced the PRSS1 gene in the proband of families without these common mutations. Novel R122C and N29T mutations were detected in independent families that segregated with the disease in an autosomal dominant fashion. The R122C mutation eliminates the arginine autolysis site as with R122H mutations. The N29T mutation may also enhance intrapancreatic trypsin activity as has been demonstrated in vitro. Identification of these new mutations requires special attention as commonly used detection methods may fail.
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PMID:Novel cationic trypsinogen (PRSS1) N29T and R122C mutations cause autosomal dominant hereditary pancreatitis. 1178 72

Hereditary pancreatitis is an autosomal dominant condition, which results in recurrent attacks of acute pancreatitis, progressing to chronic pancreatitis often at a young age. The majority of patients with hereditary pancreatitis express one of two mutations (R122H or N29I) in the cationic trypsinogen gene (PRSS1 gene). It has been hypothesised that one of these mutations, the R122H mutation causes pancreatitis by altering a trypsin recognition site so preventing deactivation of trypsin within the pancreas and prolonging its action, resulting in autodigestion. Families with these two mutations have been identified in many countries and there are also other rarer mutations, which have also been linked to hereditary pancreatitis. Patients with hereditary pancreatitis present in the same way as those with sporadic pancreatitis but at an earlier age. It is common for patients to remain undiagnosed for many years, particularly if they present with non-specific symptoms. Hereditary pancreatitis should always be considered in patients who present with recurrent pancreatitis with a family history of pancreatic disease. If patients with the 2 common mutations are compared, those with the R122H mutation are more likely to present at a younger age and are more likely to require surgical intervention than those with N29I. Hereditary pancreatitis carries a 40 % lifetime risk of pancreatic cancer with those patients aged between 50 to 70 being most at risk in whom screening tests may become important.
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PMID:Hereditary pancreatitis. 1250 40

Neonatal hypertrypsinaemia with normal sweat chloride detected during CF screening may be related to trypsin activation. We have looked for mutations of the cationic trypsinogen (PRSS1) and pancreatic secretory trypsin inhibitor (PSTI) genes in 50 hypertrypsinaemic neonates with known CFTR genotypes and negative sweat test. No mutations were found in either gene. Two silent polymorphisms were detected in the PRSS1 gene. A polymorphism in the promoter region and an intronic polymorphism of the PSTI gene were found. No difference was observed in the frequency of PRSS1 or PSTI polymorphisms in neonates carrying or not carrying CF mutations. These results do not provide an indication for an increased frequency of mutations in the PRSS1 and PSTI genes in this group of neonates with transient hypertrypsinaemia.
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PMID:Cationic trypsinogen and pancreatic secretory trypsin inhibitor gene mutations in neonatal hypertrypsinaemia. 1252 13

Pancreatitis presents clinically as acute and chronic form. A common characteristic of these two forms is enzymatic autodigestion of pancreas in the course of the disease. It results from premature activation of pancreatic digestive enzymes and disturbance of subtle balance between proteolytic enzymes and their inhibitors. The way to understand the character of mechanisms leading to development of pancreatitis has been simplified by discovery of genetic factors, which are able to initiate pathological changes at tissue level. Mutations in the PRSS1 gene (first of all R122H and N29I mutations), which encodes for cationic trypsin, cause trypsin to be protected from autodegradation. These mutations also cause precursor of trypsin - trypsinogen, to be activated easier. On the other hand mutations in the SPINK1 gene have been identified. SPINK1 gene encodes for the most important protease inhibitor of the pancreatic fluid. The most frequent mutation, namely N34S, decrease SPINK1 protein in its activity. The link between the genotype and phenotype is not clear in every case. It is probable that pancreatitis will be recognized as poligenic with many genes engaged in the disease development. Pancreatic cancer is a frequent consequence of pancreatitis. It is a very invasive cancer with high mortality. In the course of pancreatic inflammation intensive cell proliferation takes place for regeneration of pancreas damage. It is the chance for amplification of pathological changes in DNA, which have arisen as a ROS's (Reactive Oxygen Species) and RNOS's (Reactive Nitrogen Oxide Species) action effect. ROS and RNOS are generated in the course of pancreas inflammation.
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PMID:[Hereditary aspects of pancreatitis]. 1313 Jan 70

The human pancreas secretes two major trypsinogen isoforms, cationic and anionic trypsinogen. To date, 19 genetic variants have been identified in the cationic trypsinogen gene (PRSS1) of patients with hereditary, familial, or sporadic chronic pancreatitis. A common feature of cationic trypsinogen mutants studied so far is an increased propensity for autocatalytic activation (autoactivation). This is thought to lead to premature intrapancreatic digestive protease activation. In contrast, no pancreatitis-associated mutations have been found in the anionic trypsinogen gene (PRSS2), suggesting that this isoform might play a relatively unimportant role in pancreatitis. To challenge this notion, here we describe the unique properties of the E79K cationic trypsinogen mutation (c.235G>A), which was identified in three European families affected by sporadic or familial pancreatitis cases. In vitro analysis of recombinant wild-type and mutant enzymes revealed that catalytic activity of E79K trypsin was normal, and its inhibition by pancreatic secretory trypsin inhibitor was unaffected. Although the E79K mutation introduces a potential new tryptic cleavage site, autocatalytic degradation (autolysis) of E79K-trypsin was also unchanged. Furthermore, in contrast to previously characterized disease-causing mutations, E79K markedly inhibited autoactivation of cationic trypsinogen. Remarkably, however, E79K trypsin activated anionic trypsinogen two-fold better than wild-type cationic trypsin did, while the common pancreatitis-associated mutants R122H or N29I had no such effect. The observations not only suggest a novel mechanism of action for pancreatitis-associated trypsinogen mutations, but also highlight the importance of interactions between the two major trypsinogen isoforms in the development of genetically determined chronic pancreatitis.
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PMID:Interaction between trypsinogen isoforms in genetically determined pancreatitis: mutation E79K in cationic trypsin (PRSS1) causes increased transactivation of anionic trypsinogen (PRSS2). 1469 29


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