We recently identified a single R117H mutation in the cationic trypsinogen gene in several kindreds with an inherited form of acute and chronic pancreatitis (HP1), providing strong evidence that trypsin plays a central role in premature zymogen activation and pancreatitis.
Unlike in patients with hereditary pancreatitis, we found a lack of the R117H mutation in the cationic trypsinogen gene in all patients with tropical pancreatitis from Bangladesh.
The Arg(117) --> His substitution is believed to cause pancreatitis by stabilizing trypsin against autolytic degradation, while the mechanism of action of Asn(21) --> Ile has been unknown.
The Arg117-->His substitution is believed to cause pancreatitis by eliminating an essential autolytic cleavage site in trypsin, thereby rendering the protease resistant to inactivation through autolysis.
The 'self-destruct' model proposed for the R122H mutation is discussed in connection with the existing theory of pancreatitis, and the basic biochemistry and physiology of trypsinogen, with particular reference to R122 as the primary autolysis site of the cationic trypsinogen.
The 'self-destruct' model proposed for the R122H mutation is discussed in connection with the existing theory of pancreatitis, and the basic biochemistry and physiology of trypsinogen, with particular reference to R122 as the primary autolysis site of the cationic trypsinogen.
The activation peptides of the trypsinogen variants D22G and K23R could be released at a higher rate than in wild-type trypsinogen, resulting in increased amounts of trypsin in the pancreas, which could initiate pancreatitis.
Possible predisposition to pancreatitis by additional DNA variants in the gene, such as the A16V signal peptide cleavage site mutation and the K23R activation peptide cleavage site mutation is suspected, but not proven.
Possible predisposition to pancreatitis by additional DNA variants in the gene, such as the A16V signal peptide cleavage site mutation and the K23R activation peptide cleavage site mutation is suspected, but not proven.
The activation peptides of the trypsinogen variants D22G and K23R could be released at a higher rate than in wild-type trypsinogen, resulting in increased amounts of trypsin in the pancreas, which could initiate pancreatitis.
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.
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.
Segregation of the N34S mutation in families with pancreatitis is unexplained and points to a complex association between N34S and another putative pancreatitis related 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.
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.
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.
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.
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.