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Three-dimensional solution structure of ascidian trypsin inhibitor exhibits an alpha-helical structure formed by the Cys-X1-X2-X3-Cys segment representing amino acid residues 37-41. Data indicate that the secondary structure and main chain overall folding is similar to those of Kazal-type inhibitors.

Research reveals that chimeras of the alpha(sub)1-antitrypsin efficiently inhibit papain-like cysteine protease and that the inhibition is a function of the length of the reactive center loop. Data indicate that the inhibition requires insertion of the reactive center loop into the body of the cysteine protease body.

Results from the bovine pancreatic trypsin inhibitor variants indicate that the NH-aromatic interaction between amino acid residues 35 and 37 plays a role throughout protein folding in terms of stabilizing the native conformation. It also prevents any nonfunctional conformation occurring during later stages of folding.

The stabilization of the bovine pancreatic trypsin inhibitor, due to G37A point mutation, arises from the high energy conformation of A37 and disruption of the NH--aromatic--NH network. Data indicate that the Gly-Gly sequence at residues 36 and 37 and the 37 HN-35 aromatic interaction also influence the stability, folding, and dynamics of the inhibitor.

The trypsin inhibitor BSTI from Bombina bombina frog consists of 60 residues with five disulfide bonds and a secondary structure of four beta-strands arranged in two antiparallel beta-sheets. BSTI is folded into a disc shape with no hydrophobic core and the active site located in a loop made of 21-34 residues.

Results discuss alpha-amylase inhibition by the ragi alpha-amylase/trypsin bifunctional inhibitor, isolated from the millet Eleucine coracana. Data reveal that RATI competitively inhibits alpha-amylase and binds to the larger substrates of the enzyme.

Results of analysis of the 'oxidized and reduced core modules' exhibit nativelike 4:4 and non-native 3:5 beta-hairpin structure. Data further indicate that for greater fraction of the time nativelike oxidized module prevails.

Nuclear magnetic resonance spectroscopic study was utilized to describe the solution structure and backbone dynamics of the human alpha3-chain type VI collagen. Results have shown that the global fold configuration retained its form in the solution phase and assumed the same form as in the crystal phase and C5 domain core. It was indicated that the additional six residues in the N-terminal and the 12 residues in the C-terminal affected the function of the C5 domain.

The effects of serpin binding on the target proteinase particularly on the stabilization, localized enhanced conformational flexibility, and retained hydrogen bonding at the active site were established. Lower stability of rat trypsin toward thermal denaturation in the free enzyme indicated the presence of extensive protein-protein interactions that stabilize the folding process for the complex.

A hydrophobic cluster in the denatured state promotes the formation of a kinetically important intermediate in the early stages of the folding of bovine pancreatic trypsin inhibitor (BPTI) and BPTI-like domains. A series of 24 mutants of BPTI were examined to identify the amino acids which contribute to the fast formation of residues 14-38. The formation of 14-38 disulfide is found to be accelerated by the seven nonpolar or aromatic residues, away from the cysteines by as many as eight residues. The acceleration of the formation of 14-38 disulfide occurred without changing the reactivities of the cysteines.

The water 17O and 2H nuclear magnetic relaxation measured over the Larmor frequency range, 2.6-49 MHz in the solution of bovine pancreatic trypsin inhibitor and G36S mutants to investigate the effect of exchange of 4 internal water molecules present in BPTI shows that the residence time of W122 is between 10-200 micro sec and that of W111, W112 and W113 is between 0.015-1.0 micro sec. The shift of the protein backbone from its normal position is slow in 14-38 disulfide bond region of BPTI. Elimination of W122 reduces the amplitude of 2H dispersion but has no effect on the 17O dispersion.

Multidimensional 1H and 15N NMR spectroscopic determination of the three-dimensional structure of bifunctional alpha-amylase/trypsin inhibitor(RBI) from ragi seeds shows that the secondary structure of RBI contains alpha-helical and beta-structure element. The three dimensional fold and the secondary topology of alpha amylase is different from that of the typical serine proteinase inhibitors indicating that the reactive peptide bond involved in trypsin binding has no effect on the overall structure of the inhibitor.

Soybeans are high in protein but also contain a number of minor constituents traditionally considered to be antinutritional factors. These include trypsin inhibitors, phytic acid, saponins and isoflavones. These compounds are now thought to have beneficial biological effects in the diet, such as lowering blood cholesterol or preventing cancer. Soybean processing changes the content of these minor constituents in various ways. This review discusses the changes in content of trypsin inhibitors, phytic acid, saponins and isoflavones as soybeans are processed into the conventional protein ingredients, flours, concentrates and isolates, as well as some of the traditional Oriental soybean foods. INDEXING KEY WORDS: soybean; isoflavone; phytic acid; saponin; trypsin inhibitor

The synthesis of disulfide bonds in secreted proteins of Escherichia coli requires the presence of DsbA protein present in the periplasm of Escherichia coli. Two cysteine residues form a unstable disulfide bond in the Escherichia coli. The cysteine residues introduce the disulfide bonds in proteins.

Replacement of tyrosine 35 with leucine residue in a bovine pancreatic trypsin inhibitor (BPTI) variant blocks the aggregation of two of the native-like intermediates in the BPTI folding pathway. The absence of these native-like intermediates enhances folding rates for BPTI. Y35L replacement restricts the aggregation of proteins (30-51, 14-38) and (5-55, 14-38) and thus accelerates disulfide synthesis. The amino acid residues' rearrangement does not influence the pathway of folding or disulfide formation.

Almost all in vitro and in vivo assay systems reveal the occurrence of biologically active peptides, which can be studied in an orderly manner by synthetic peptide combinatiorial libraries. Trypsin is employed as a model enzyme to study the utility of this process to recognize the peptide enzyme hindering factors. Cotton carriers are used to prepare a particularly designed library with hexapeptide combinations. The connection of the deprotected peptides to the cotton carrier is maintained by changing the synthetic approach with cotton as a solid support. There are several separate hexapeptides with trypsin hindering activity.

Bovine pancreatic trypsin inhibitor, BPTI, reveals the folding and unfolding of proteins, which is examined by a novel process. The size of the protein helps in determining the properties of unfolding and refolding of the original conformation. The size of the protein is referred to as the three important radii of the ellipsoid. A process involving minimization of a dimensional-constraint energy is used to refold the extended and deformed structure to the original conformation. This results in a distinct and reproducible unfolding pathway for the interface of BPTI without a disulfide bond.

Structured folding intermediates which are kinetically trapped are rearranged, and disulfide bond formation is catalyzed by protein disulfide isomerase (PDI). The retinol-binding protein and the structured intermediates of bovine pancreatic trypsin inhibitor undergo enhanced reductive unfolding due to PDI. The rate of disulfide bond formation remains almost unaffected by PDI.

Soymilk samples which were exposed to pH 7.5, 6.5 and 2 and subjected to heat treatment and indirect ultra high temperature, revealed its trypsin inhibitor activity, which was less heat-liable at low pH than at high pH, when heated at 93 degree Celsius, 121 degree Celsius and 132 degree Celsius. When the holding temperature was enhanced to 143 degree Celsius and 154 degree Celsius, the influence of pH on the rate of thermal inactivation was not as decisive.

The results of molecular dynamics simulations of bovine pancreatic trypsin inhibitor in water and chloroform were presented. It was shown that there is only a very small difference in backbone flexibility between protein in both aqueous and nonaqueous solutions. It was proposed that the major difference between the two solvent environments is the preferred orientations of the amino acid side chains.

The folding of bovine pancreatic trypsin inhibitor (BPTI) involves a series of disulfide bond intermediates. The two dimensional structure of an analogue of one of the crucial intermediates, which contains a disulfide bond between the Cys-30 and Cys-51 residues, was determined by 1H NMR. The results showed that the (30-51) intermediate is a true partially folded intermediate, which also contains the main structural elements of the fully folded molecule. The location and nature of the folded regions demonstrated the importance of interactions between elements of native-like secondary structure in protein folding.

A pH-dependent His25-Tyr27 interaction was demonstrated in the Cucurbita maxima trypsin inhibitors (CMTI-I and CMTI-III) by nuclear magnetic resonance spectroscopy. On the basis of peak shapes, line widths, deuterium exchange kinetics and nuclear Overhauser effect data, it was shown that an interaction between His25 and Tyr27 is triggered by the ionization of the histidine residue and that a hydrogen bond is formed between OH of Tyr27 and N(epsilon) of His25. Moreover, the relative orientations of His25 and Tyr27 arerelevant, because trypsin is active only above pH 6.

The solution structure of reactive-site hydrolyzed Cucurbita maxima trypsin inhibitor III (CMTI-III) was investigated by two-dimensional proton nuclear magnetic resonance spectroscopy. It was shown that both the reactive-site peptide bond cleavage and the substitution of Glu9 by Lys lead to chemical shift changes, causing tertiary structural changes for residues located near and far from the reactive site. However, the secondary structural elements are not affected.

The bioavailability of calcium of three varieties of Phaseolus vulgaris are determined. Results show that availability of calcium from legumes is unaffected by trypsin inhibitors or tannins. Sometimes, reduced availability of calcium from legumes may be due to phytate and/or oxalate content. Although legumes may be impractical as sole sources of calcium in the diet, their contribution towards positive calcium balance is significant.

The distribution of various ions around two proteins, horseradish peroxidase (HRP) and bovine pancreatic trypsin inhibitor (BPTI) is investigated by means of molecular dynamics simulations. Although the two proteins under investigation are very different from each other, the ion distributions around them are remarkably similar.

In [Alpha]1-AT deficiency, a misfolded but functionally active mutant [Alpha]1-ATZ ([Alpha]1-ATZ) molecule is retained in the endoplasmic reticulum of liver cells rather than secreted into the blood and body fluids. Emphysema is thought to be caused by the lack of circulating [Alpha]1-AT to inhibit neutrophil elastase in the lung. Liver injury is thought to be caused by the hepatotoxic effects of the retained [Alpha]1-ATZ. In this study, we show that several 'chemical chaperones,' which have been shown to reverse the cellular mislocalization or misfolding of other mutant plasma membrane, nuclear, and cytoplasmic proteins, mediate increased secretion of [Alpha]1-ATZ. In particular, 4-phenylbutyric acid (PBA) mediated a marked increase in secretion of functionally active [Alpha]1-ATZ in a model cell culture system. Moreover, oral administration of PBA was well tolerated by PiZ mice (transgenic for the human [Alpha]1-ATZ gene) and consistently mediated an increase in blood levels of human [Alpha]1-AT reaching 20-50% of the levels present in PiM mice and normal humans. Because clinical studies have suggested that only partial correction is needed for prevention of both liver and lung injury in [Alpha]1-AT deficiency and PBA has been used safely in humans, it constitutes an excellent candidate for chemoprophylaxis of target organ injury in [Alpha]1-AT deficiency.

Computations were performed for a series of conformations and various crystal structures of bovine pancreatic trypsin inhibitor (BPTI) and hen egg white lysozyme (HEWL). The goal was to investigate the influence of the multiminimum surface of the protein native state on the normal modes. Findings showed that the conformational space spanned by the 75 (BPTI) and 130 (HEWL) low-frequency normal modes, which account for about 90% of the atomic fluctuations, is relatively invariant with respect to various conformations in the native state manifold.

The application of the synchronous nutation method in the measurement of cross relaxation rates (Overhauser effects) between different, nonneighboring amino acids in a protein was reported. It was shown that spin diffusion effects in measurement of Overhauser effects by nuclear magnetic resonance in solution can be suppressed with this method. The time dependence of the magnetization of H(super alpha)(Cys-30) in basic pancreatic trypsine inhibitor, as a function of the duration of synchronous nutation of H(super alpha)(Tyr-23) and H(super alpha)(Cys-30), is demonstrated.