Trypsin inhibitor basic pancreatic

Figure 5.37 (a) Conventional phase-sensitive COSY spectrum of basic pancreatic trypsin inhibitor, (b) Double-quantum filtered (DQF) phase-sensitive COSY spectrum of the same trypsin inhibitor, in which singlet resonances and solvent signal are largely suppressed. Notice how clean the spectrum is, especially in the region near the diagonal line. (Reprinted from Biochem. Biophys. Res. Comm. 117, M. Ranee, et al., 479, copyright (1983) with permission from Academic Press, Inc.)... 

Fig. 2. Stereo drawing of all nonhydrogen atoms of basic pancreatic trypsin inhibitor. The main chain is shown with heavy lines and side chains with thin lines.

Fig. 53. The main chain hydrogen bonds of basic pancreatic trypsin inhibitor, plus two of the side chains whose hydrogen bonds stabilize the ends of pieces of secondary structure Ser-47 at the beginning of an a-helix and Asn-43 at the end of a fi strand.

Fig. 103. Basic pancreatic trypsin inhibitor as an example of a small disulfide-rich structure, (a) a-Carbon stereo (b) backbone schematic, viewed as in a, with disulfides shown as zig-zags. Figure 2 shows an all-atom stereo of this protein with side chains.

Several inhibitor-protease complexes have been crystallized and details of their interactions are known. For example, the pancreatic trypsin inhibitor binds at the active site of trypsin with K( >1013 M-1 at neutral pH 496 Tire two molecules fit snugly together,490 497 the inhibitor being bound as if it were a peptide substrate with one edge of the inhibitor molecule forming an antiparallel (1 structure with a peptide chain in the enzyme. Lysine 15, which forms part of this P structure, enters the specific Pj binding site for a basic amino acid in a substrate. Thus, the protease inhibitor is a modified substrate which may actually undergo attack at the active site. However, the fit between the two... 

Many inhibitors with very low dissociation constants appear to have a slow onset of inhibition when they are added to a reaction mixture of enzyme and substrate. This was once interpreted as the inhibitors having to induce a slow conformational change in the enzyme from a weak binding to a tight binding state. But in most cases, the slow binding is an inevitable consequence of the low concentrations of inhibitor used to determine its Ki. For example, consider the inhibition of trypsin by the basic pancreatic trypsin inhibitor. Kx is 6 X 10-14 M and the association rate constant is 1.1 X 106 s-1 M-1 (Table 4.1). To determine the value of Ki, inhibitor concentrations should be in the range of K1, where the observed first-order rate constant for association is (6 X Q U M) X (1.1 X 106 s-1 M-1) that is, 6.6 X 10-8 s 1. The half-life is (0.6931/6.6) X 108 s, which is more than 17 weeks. 

Therapeutic Function Proteinase inhibitor Chemical Name Trypsin inhibitor, pancreatic basic Common Name Aprotinin Frey inhibitor Kallikrein-trypsin inhibitor Chemical Abstracts Registry No. 9087-70-1... 

After a demonstration of the method s abilities on simulated data,8 the algorithm was soon applied to several cases with real data such as metal-lothionein,32 tendamistat,33 and basic pancreatic trypsin inhibitor (BPTI).34 Furthermore, aside from the original program, DISMAN,8 the basic algorithm has been implemented in other programs such as DADAS35 and the... 

G. Wagner, W. Braun, T. F. Havel, T. Schaumann, N. Go, and K. Wiithrich, /. Mol. Biol., 196, 611 (1987). Protein Structures in Solution by Nuclear Magnetic Resonance and Distance Geometry The Polypeptide Fold of the Basic Pancreatic Trypsin Inhibitor Determined Using Two Different Algorithms. DISGEO and DISMAN. 

Ttlchsen E, Woodward C (1987) Assignment of asparagine-44 side-chain primary amide. N NMR resonances and the peptide amide. N H resonance of glycine-37 in basic pancreatic trypsin inhibitor. Biochemistry 26 1918-1925... 

Using trypsinogen as biocatalyst under similar conditions in the dropping experiment, after 400 min analytical HPLC showed 21% of 26 and 79% of 25. The conversion of the acyl donor ester was only 80%. Preparative RP-HPLC provided 26 yield Img (7%). The determined amino acid composition corresponded with the calculated values. In the appropriate batch experiment the analytical yield was 17% of 26 (95% conversion of 24), whereas the application of trypsinogen inhibited by basic pancreatic trypsin inhibitor provided only 8% of 26 after 24 h at 48% conversion of the acyl donor ester 24. Using trypsin instead of the zymogen, after approximately 20 min, more than 50% of 26 (after Imin, 20% product formation at 100% conversion of 24) and 25 were digested. 

Johann Deisenhofer received his Diploma in Physics from the Technical University of Munich in 1971 and his Dr. rer. nat. degree in 1974 from the Technical University of Munich for research done at the Max-Planck-Institute for Biochemistry in Martinsried under Robert Huber. His thesis work was the structure refinement of the basic pancreatic trypsin inhibitor at 1.5 angstrom resolution. He worked as a Research Associate and then as Staff Scientist at the Max Planck Institute between 1974 and 1988. He habilitated at the Technical University Munich in 1987. He has been at the University of Texas Southwestern Medical Center at Dallas since 1988. 

For example, from protein basic pancreatic trypsin inhibitor (BPTI), four experimental ISNets are observed from a double quantum filtered COSY spectrum as shown at the bottom of Fig. 6. No one of them is completely matched onto its ISNet cluster center. 

Basic pancreatic trypsin inhibitor (trasylol) has been used in affinity chromatography to purify human leukocyte elastase, however, confllc-... 

Figure 6. Contour plot of a proton 2D NOE spectrum at 360 MHz of the basic pancreatic trypsin inhibitor. The protein concentration was 0.02 M solvent, HiO ...

Wagner, G., WUthrich, K. (1982) Amide proton exchange and surface conformation of the basic pancreatic trypsin inhibitor in solution studies with two-dimensional nuclear magnetic resonance. J Mol Biol, 160 (2), 343-361. 

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