Rabbit Anti-Trypsinogen
Trypsinogen (EC 3.4.23.18/20/21/23/24/26) is the precursor form or zymogen of the pancreatic enzyme trypsin. It is found in pancreatic juice, along with amylase, lipase, and chymotrypsinogen. It is activated by enteropeptidase, which is found in the intestinal mucosa, to form trypsin. Once activated, the trypsin can activate more trypsinogen into trypsin. Trypsin cleaves the peptide bond on the carboxyl side of basic amino acids such as arginine and lysine. Trypsinogen, as a precursor of trypsin, functions as storage of an inactive form of trypsin so that it may be kept in pancreas and released in significant amount when required for protein digestion. Trypsinogen is activated by enterokinase. Enterokinase is produced by the mucosa of duodenum and it cleaves the peptide bond of trypsinogen after residue 15 which is a lysine. The N-terminal peptide is discarded, and a slight rearrangement of the folded protein occurs. The newly-formed N-terminal residue (residue 16) insert into a cleft where its α-amino group forms an ion pair with the aspartate near the active site serine, and results in the conformational rearrangement of other residues. The amino group of Gly 193 orientates itself into the correct position which completes the oxyanion hole in active site, thereby activating the protein.[1] Since trypsin also cleaves the peptide bond after an arginine or a lysine, it can cleave other trypsinogen, and the activation process therefore becomes autocatalytic.
Trypsin is produced, stored and released as the inactive trypsiongen to ensure that the protein is only activated in the appropriate location. Premature trypsin activation can be destructive and may trigger a series of events that lead to pancreatic self-digestion. In normal pancreas, around 5% of trypsinogens are thought to get activated, therefore there are a number of defenses against such inappropriate activation. Trypsinogen is stored in intracellular vesicles in the pancreas called zymogen granules whose membranous walls are thought to be resistant to enzymatic degradation. A further safeguard against inappropriate trypsin activation is the presence of inhibitors such as bovine pancreatic trypsin inhibitor (BPTI) and serine protease inhibitor Kazal-type 1 (SPINK1) which binds to any trypsin formed. Trypsin autocatalytic activation of trypsinogen is also a slow process due to the presence of a large negative charge on the conserved N-terminal hexapeptide of trypsinogen which repels the aspartate on the back of trypsin's specificity pocket.[2] Trypsin may also inactivate other trypsin by cleavage.
Applications
Suitable for use in ELISA, Western Blot, Dot Blot, Conjugation, Immunoprecipitation. Other applications not tested.
Recommended Dilution
ELISA: 1:1000-1:10,000 Western Blot: 1:2000-1:10,000 using 1ug Trypsinogen Optimal dilutions to be determined by the researcher.
Storage and Stability
May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.
Immunogen
Trypsinogen from bovine pancreas
Form
Supplied as a liquid in PBS, pH 7.2, 0.01% sodium azide. No stabilizer added.
Purity
Purified from monospecific antiserum by delipidation, fractionation and ion exchange chromatography.
Specificity
Recognizes Trypsinogen. Assay by immunoelectrophoresis resulted in a single precipitin arc against anti-rabbit serum as well as purified and partially purified trypsinogen (bovine pancreas).
