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 is a persistent inflammatory disorder of the pancreas, characterized by destruction of the pancreatic parenchyma, maldigestion, chronic pain and diabetes mellitus. Genetic factors determining susceptibility to chronic pancreatitis can be classified in two groups: 1. rare gene mutations affecting the cationic trypsinogen gene that directly cause the disease, and 2. genetic variants that increase the risk for chronic pancreatitis but require additional risk factors to precipitate the disease. These gene variants are considered genetic risk factors, which emerged during the past decade and now represent a clinically important etiological category. Susceptibility to chronic pancreatitis is inherited in a complex manner, which can involve alterations in several genes conferring various degrees of risk. The biochemical mechanism behind the genetic risk includes increased ectopic activation of the digestive enzyme trypsin in the pancreas and failure of protective mechanisms responsible for trypsin inactivation.
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PMID:[Genetic risk factors in chronic pancreatitis]. 1875 60

Human pancreatic trypsinogens undergo post-translational sulfation on Tyr(154), catalysed by the Golgi-resident enzyme tyrosylprotein sulfotransferase 2. Sequence alignments suggest that the sulfation of Tyr(154) is facilitated by a unique sequence context which is characteristically found in primate trypsinogens. In the search for genetic variants that might alter this sulfation motif, we identified a single nucleotide polymorphism (c.457G>C) in the PRSS2 (serine protease 2, human anionic trypsinogen) gene, which changed Asp(153) to a histidine residue (p.D153H). The p.D153H variant is common in subjects of African origin, with a minor allele frequency of 9.2%, whereas it is absent in subjects of European descent. We demonstrate that Asp(153) is the main determinant of tyrosine sulfation in anionic trypsinogen, as both the natural p.D153H variation and the p.D153N mutation result in a complete loss of trypsinogen sulfation. In contrast, mutation of Asp(156) and Glu(157) only slightly decrease tyrosine sulfation, whereas mutation of Gly(151) and Pro(155) has no effect. With respect to the biological relevance of the p.D153H variant, we found that tyrosine sulfation had no significant effect on the activation of anionic trypsinogen or the catalytic activity and inhibitor sensitivity of anionic trypsin. Taken together with previous studies, the observations of the present study suggest that the primary role of trypsinogen sulfation in humans is to stimulate autoactivation of PRSS1 (serine protease 1, human cationic trypsinogen), whereas the sulfation of anionic trypsinogen is unimportant for normal digestive physiology. As a result, the p.D153H polymorphism which eliminates this modification could become widespread in a healthy population.
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PMID:A common African polymorphism abolishes tyrosine sulfation of human anionic trypsinogen (PRSS2). 1898 5

We have developed a protocol to assemble in one step and one tube at least nine separate DNA fragments together into an acceptor vector, with 90% of recombinant clones obtained containing the desired construct. This protocol is based on the use of type IIs restriction enzymes and is performed by simply subjecting a mix of 10 undigested input plasmids (nine insert plasmids and the acceptor vector) to a restriction-ligation and transforming the resulting mix in competent cells. The efficiency of this protocol allows generating libraries of recombinant genes by combining in one reaction several fragment sets prepared from different parental templates. As an example, we have applied this strategy for shuffling of trypsinogen from three parental templates (bovine cationic trypsinogen, bovine anionic trypsinogen and human cationic trypsinogen) each divided in 9 separate modules. We show that one round of shuffling using the 27 trypsinogen entry plasmids can easily produce the 19,683 different possible combinations in one single restriction-ligation and that expression screening of a subset of the library allows identification of variants that can lead to higher expression levels of trypsin activity. This protocol, that we call 'Golden Gate shuffling', is robust, simple and efficient, can be performed with templates that have no homology, and can be combined with other shuffling protocols in order to introduce any variation in any part of a given gene.
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PMID:Golden gate shuffling: a one-pot DNA shuffling method based on type IIs restriction enzymes. 1943 41

Chronic pancreatitis (CP) is a persistent inflammation of the pancreas. Over the past 12 years, genetic studies of hereditary, familial, and idiopathic forms of CP have made great progress in defining the disease pathogenesis. Identification of gain-of-function missense and copy number mutations in the cationic trypsinogen gene (PRSS1) and loss-of-function variants in both the pancreatic secretory trypsin inhibitor (SPINK1) and chymotrypsinogen C (CTRC) genes has firmly established the pivotal role of prematurely activated trypsin within the pancreas in the etiology of CP. Loss-of-function variants in the cystic fibrosis transmembrane conductance regulator (CFTR) and calcium-sensing receptor (CASR) genes also increase the risk of CP. Here, we review recent developments in this rapidly evolving field, highlight the importance of gene-gene and gene-environment interactions in causing the disease, and discuss the opportunities and challenges in identifying novel genetic factors that affect susceptibility/resistance to CP.
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PMID:Chronic pancreatitis: genetics and pathogenesis. 1945 52

Mutations in the activation peptide of human cationic trypsinogen have been found in patients with chronic pancreatitis. Previous biochemical studies demonstrated that mutations p.D19A, p.D22G, and p.K23R strongly stimulate trypsinogen autoactivation. In the present study, we characterized the cell biological effects of these mutants using human embryonic kidney 293T and AR42J rat acinar cells. We found that relative to wild-type trypsinogen, secretion of the mutants from transfected cells was markedly decreased. This apparent secretion defect was completely rescued by inhibition of autoactivation via (1) inclusion of the small molecule trypsin inhibitor benzamidine in the growth medium; or (2) cotransfection with the physiological trypsin inhibitor SPINK1; or (3) by mutation of the catalytic Ser(200) residue in trypsinogen. In contrast, extracellularly added SPINK1 or other nonpermeable proteinaceous trypsin inhibitors did not restore normal secretion of the mutants, indicating that intracellular autoactivation is responsible for the observed secretion loss. Acinar cells expressing the p.D22G mutant detached from the culture plate over time, became terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling-positive, and exhibited elevated levels of the proapoptotic transcription factor CHOP. The observations indicate that activation peptide mutants of human cationic trypsinogen undergo autoactivation intracellularly, which leads to decreased trypsinogen secretion and eventual acinar cell death. The results thus define a novel pathological pathway for parenchymal injury in hereditary chronic pancreatitis.
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PMID:Intracellular autoactivation of human cationic trypsinogen mutants causes reduced trypsinogen secretion and acinar cell death. 1980 34

One anionic and one cationic dog trypsin have been identified in dog pancreatic juice and isolated. The dog pancreatic juice contained 1.4 mg/ml of anionic trypsinogen and 1.0 mg/ml of cationic trypsinogen, respectively. The conversion of the trypsinogens to active enzymes is autocatalytic with the formation of active enzymes with higher isoelectric points than the zymogens. Although the amino acid compositions of the two trypsins were similar to those of other mammalian trypsins, a significant difference in content of acidic and basic amino acids, respectively, was found between the two dog trypsins. A high extent of cross-inhibition of the dog trypsins and of bovine trypsin by antibodies to each of the dog trypsins indicated immunological cross-reaction between the various trypsins despite lack of demonstrable cross-precipitation in gels. The calculated s(20,w)0 value for both dog trypsins was 3.3 S. The Km value of anionic trypsin for benzoyl-D,L-arginine-p-nitroanilide' HCl was found to be similar to that of cationic trypsin and to that of bovine cationic trypsin. Soybean trypsin inhibitor, chicken ovomucoid, porcine and bovine secretory inhibitors are potent inhibitors of anionic and cationic dog trypsin.
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PMID:Anionic and cationic dog trypsin. Isolation and partial characterization. 1999 18

Chronic pancreatitis (CP) is a clinical situation with persisting inflammation leading to destruction of the pancreas ensuing endocrine and exocrine failure. There are 4 subtypes: hereditary, idiopathic, alcoholic and tropical pancreatitis. Genetic factors can explain a significant proportion of CP cases. The PRSS1 gene, encoding cationic trypsinogen, was found to be correlated with hereditary CP. This signalled the extensive search for other candidate genes within the trypsin pathway. Genes like SPINK1 and CTRC are associated with CP and should be considered as important contributing factors rather than causative. The search for candidate genes not part of the trypsin pathway has been less successful and the only gene consistently associated with CP is the Cystic Fibrosis Transmembrane Regulator. In this review we will discuss the various CP subtypes in relation to the respective genetic variants. This review will also address the implications of genetic testing in daily clinical practise.
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PMID:Genetic factors in chronic pancreatitis; implications for diagnosis, management and prognosis. 2051 Aug 27

In the past, chronic pancreatitis has been regarded as a fairly uniform and largely untreatable disorder that most commonly affects patients who both lack gainful employment or adequate insurance coverage and have a tendency to smoke and drink. Large clinical trials suggest that this perception is not only misguided and discriminatory but also not based on facts. We forgot that the perception of chronic liver disease was similar before World War II, and just like liver cirrhosis the fibrosis and cirrhosis of the pancreas--i.e. chronic pancreatitis--is the end result of a range of environmental, inflammatory, infectious and genetic disorders. A growing number of these have only recently been recognized as a distinct entity and several of which are becoming truly treatable. A large proportion of the risk for developing pancreatitis is conveyed by genetic risk factors, and we estimate that less than half of those have been identified so far. The same holds true for protective factors that can prevent pancreatitis, even in the face of excessive alcohol abuse. Various gene mutations and polymorphisms appear to determine an individual's susceptibility for developing pancreatic disease, for the severity of the disease, and for the disease progression. The spectrum of genotype/phenotype associations ranges from straightforward autosomal dominant traits with near-complete penetrance, as for the most common mutations in the cationic trypsinogen gene (PRSS1), to moderate risks factors without mendelian inheritance patterns, as for SPINK1 and CFTR mutations, to very subtle risk associations and disease modifiers that can only be identified in large cohort studies, as for the chymotrypsin C, calcium-sensing receptor and the anionic trypsin (PRSS2) mutations. Only a better understanding of the disease mechanisms that underlie these changes will make an individualized therapy of pancreatic disorders a realistic option.
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PMID:Advances in the etiology of chronic pancreatitis. 2081 6

It is now generally believed that pancreatitis results from pancreatic autodigestion. An inappropriate conversion of pancreatic zymogens to active enzymes within the pancreatic parenchyma is thought to initiate the inflammatory process. A key role has been attributed to the activation of trypsinogen to trypsin, converting all proteolytic proenzymes to their active form. Several gain-of-function mutations in the cationic trypsinogen gene (PRSS1) have been identified in patients with chronic pancreatitis (CP). These mutations lead to enhanced intrapancreatic trypsinogen activation. In contrast, a variant in the anionic trypsinogen (PRSS2) gene, p.G191R, has been described that mitigates intrapancreatic trypsin activity and thereby plays a protective role. Beside trypsinogen mutations, loss-of-function variants in SPINK1, encoding a pancreatic trypsin inhibitor, are strongly associated with idiopathic CP. Approximately 15-40% of patients with so-called idiopathic CP carry p.N34S on one allele or on both alleles. Chymotrypsin C (CTRC) degrades all human trypsin isoforms with high specificity. Two CTRC alterations, p.R254W and p.K247_R254del, are significantly associated with idiopathic as well as alcohol-related CP. Functional analysis of the variants revealed impaired activity and/or reduced secretion. Thus, loss-of-function mutations in CTRC predispose to pancreatitis by diminishing its protective trypsin-degrading activity. Albeit the association between CFTR, the gene mutated in cystic fibrosis, and idiopathic CP is now well established, the pathogenic mechanisms are poorly understood. Nearly 25-30% of patients carry at least one CFTR mutation, but few patients only were compound-heterozygous. Several patients, however, are trans-heterozygous for a CFTR alteration and a PRSS1, SPINK1, or CTRC variant, respectively.
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PMID:Genetics of pancreatitis: a guide for clinicians. 2152 53

Genetic risk factors of chronic pancreatitis (CP) have been identified and a number of studies have found that CP can lead to pancreatic cancer. Therefore, the detection of pancreatitis-associated gene mutations can aid the pancreatic cancer diagnostic process. Mutations in three genes, the cationic trypsinogen (PRSS1) gene, the cystic fibrosis transmembrane conductance regulator (CFTR) gene and the pancreatic secretory trypsin inhibitor (SPINK1) gene, have been identified as risk factors for CP. The aim of this study was to describe specific novel mutations in the intron of the PRSS1 gene in patients with pancreatic cancer and CP. A total of 65 unrelated patients with pancreatic cancer and 29 with CP were reviewed. Mutations and polymorphisms of the PRSS1 gene were analyzed by direct sequencing. Information regarding clinical data and smoking exposure was collected by personal interviews using a structured questionnaire. IVS 3+36 A>G mutation in the PRSS1 gene was found in 2 cases with pancreatic cancer, and these 2 patients were classified as never-smokers. IVS 3+127 T>A and IVS 3+157 G>C double mutations were identified in one patient with CP. All patients were found to have serum trypsin levels lower than that of the normal controls. Therefore, the PRSS1 gene mutation may be a special common cause of pancreatic cancer and CP.
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PMID:PRSS1 intron mutations in patients with pancreatic cancer and chronic pancreatitis. 2210 5


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