胰蛋白酶原 来源于牛胰腺，1G，T1143-1G，Sigma

General description

Trypsinogen is a proenzyme (zymogen) that is activated to form trypsin. It is synthesized in the pancreas and activated by enterokinase once it reaches the lumen of the small intestine. Bovine trypsinogen is a single polypeptide chain of 229 amino acids that is cross linked by six disulfide bridges. Enterokinase cleaves a hexapeptide to from the NH₂ terminus of trypsinogen at the Lys6 - Ile7 peptide bond and activates it. Trypsin, thus formed, autocatalytically activates more trypsinogen to trypsin. This native form of trypsin is called β-trypsin, which undergoes autolysis at Lys₁₃₁ - Ser₁₃₂ resulting in α-trypsin that is held together by disulfide bridges. Trypsin is a serine protease with His₄₆ and Ser₁₈₃ at the active site. The pH optimum of trypsin is 7 - 9.

Application

Trypsinogen from bovine pancreas is suitable for use in:

• the secondary structure analysis of proteins in H2O solution using single-pass attenuated total reflection Fourier transform infrared (ATR-FT-IR) microscopy
• tuning and calibration of electrospray ionization quadrupole time-of-flight (ESI-Q-TOF) mass spectrometer
• the secondary structure analysis of proteins by infrared (IR) spectroscopy
• SDS-PAGE as a molecular weight standard (24kDa)

Biochem/physiol Actions

Phytic acid complexed with calcium has been shown to increase the secretion of trypsinogen unable to be cleaved for activation. It also reduced the stabilization effect of calcium on activated trypsin. The active form of trypsinogen, referred to as trypsin, cleaves peptides on the C-terminal side of lysine and arginine amino acid residues. It also hydrolyzes ester and amide linkages of synthetic derivatives of amino acids such as, benzoyl L-arginine ethyl ester (BAEE), p-toluenesulfonyl-L-arginine methyl ester (TAME), etc.

Other Notes

One BAEE unit is equal to a ΔA₂₅₃ of 0.001 per min with BAEE as substrate at pH 7.6 at 25 °C and a reaction volume of 3.2 mL (1 cm light path).