Ctrc dating ru Free sex cam cougar chat
The human pancreas expresses two major trypsinogen isoforms, cationic trypsinogen (PRSS1) and anionic trypsinogen (PRSS2).
Mutations in PRSS1 cause hereditary pancreatitis by altering cleavage of regulatory nick sites by chymotrypsin C (CTRC) resulting in reduced trypsinogen degradation and increased autoactivation.
Trypsinogen is activated to trypsin in the duodenum by the serine protease enteropeptidase, and active trypsin serves not only as the most abundant digestive protease but also as an activator of other proteolytic zymogens (7).
Trypsinogen can undergo autoactivation, a self-amplifying bimolecular reaction in which trypsin activates trypsinogen to yield two trypsin molecules.
Although prior studies demonstrated that human anionic trypsinogen also undergoes autoactivation (17–19), purity of native trypsinogen preparations was uncertain, and recombinant preparations differed from the native proenzyme in their N termini due to cloning considerations and unwanted processing by bacterial aminopeptidases.
The discovery of the association of PRSS1 mutations and hereditary pancreatitis stimulated a number of investigations into the potential role of PRSS2 in chronic pancreatitis (14–16).
Increased sensitivity of anionic trypsinogen to CTRC-mediated degradation was due to an additional cleavage site at Leu-148 in the autolysis loop and the lack of the conserved Cys-139–Cys-206 disulfide bond.
Significant stabilization of anionic trypsinogen against degradation was achieved by simultaneous mutations of CTRC cleavage sites Leu-81 and Leu-148, autolytic cleavage site Arg-122, and restoration of the missing disulfide bridge.
This stands in stark contrast to cationic trypsinogen where single mutations of either Leu-81 or Arg-122 resulted in almost complete resistance to CTRC-mediated degradation.
Finally, processing of the trypsinogen activation peptide at Phe-18 by CTRC inhibited autoactivation of anionic trypsinogen, although cationic trypsinogen was strongly stimulated.
Search for ctrc dating ru:
Active cationic trypsin is also degraded by this mechanism but at a much slower rate due to unusual thermodynamic stability of the regulatory nick sites (11, 12).