Seeds of various wild and cultivated pulses express varied degrees of resistance to damage by Callosobruchus maculatus, a major pest of stored pulses. Seeds were analysed for trypsin/chymotrypsin inhibitors (qualitatively and quantitatively) and protein pro®les (SDS-polyacrylamide gel electrophoresis) to study the chemical basis of resistance to bruchid infestation. Seeds of the wild pulses Dun...

A low molecular weight serine protease inhibitor, named trypstatin, was purified from rat peritoneal mast cells. It is a single polypeptide with 61 amino acid residues and an Mr of 6610. Trypstatin markedly inhibits blood coagulation factor Xa (Ki = 1.2 x 10(-10) M) and tryptase (Ki = 3.6 x 10(-10) M) from rat mast cells, which have activities that convert prothrombin to thrombin. It also inhib...

Cystine-knot miniproteins define a class of bioactive molecules with several thousand natural members. Their eponymous motif comprises a rigid structured core formed by six disulfide-connected cysteine residues, which accounts for its exceptional stability towards thermic or proteolytic degradation. Since they display a remarkable sequence tolerance within their disulfide-connected loops, these...

Soybean trypsin inhibitors are thought to ward off pathogens. Studies with aflatoxigenic strains of Aspergillus flavus and A. parasiticus, frequent soybean contaminants, revealed that trypsin inhibitors do not affect the growth of these fungi and aflatoxin production. Further, the availability of zinc, an essential mineral for aflatoxin synthesis that was thought to explain increased aflatoxin ...

The first total synthesis of MCoTI-II, a cysteine knot microprotein and potent trypsin inhibitor, is described; a synthetic strategy has been developed that combines efficient backbone construction via optimised solid phase peptide synthesis with one-pot 'thia-zip' native chemical ligation and refolding to yield the natural product.

Modtication of the tyrosyl and amino groups of trypsin and soybean trypsin inhibitor (Kunitz) with N-acetylimidazole before and after their combination was used to assess the role of these amino acids in the binding process. Trypsin was inactivated by au excess of the inhibitor and the complex isolated by chromatography on Sephadex G-75, at pH 6.8. Prior to complex formation, trypsin and the in...

MCoTI-II is a head-to-tail cyclic peptide with potent trypsin inhibitory activity and, on the basis of its exceptional proteolytic stability, is a valuable template for the design of novel drug leads. Insights into inhibitor dynamics and interactions with biological targets are critical for drug design studies, particularly for protease targets. Here, we show that the cyclization and active sit...

Simulation of the molecular dynamics of a small protein, bovine pancreatic trypsin inhibitor, was found to be more realistic when water molecules were included than when in vacuo: the time-averaged structure was much more like that observed in high-resolution x-ray studies, the amplitudes of atomic vibration in solution were smaller, and fewer incorrect hydrogen bonds were formed. Our approach,...

Alkyl substituted 2-halogen-4-nitro-phenols (like bromonitrothymol) are potent inhibitors of photosynthetic electron flow in chloroplasts. There inhibition site is identical to that of DCMU, though the phenols do not contain their essential chemical element responsible for inhibition nor do they follow their correlation of chemical structure and biochemical function. Binding of labelled metribu...

1. Amylase (EC 3.2.1.1) activity found in the intestinal tract of chicks posterior to the stomach is of endogenous origin, as amylase in the food is inactivated by the low pH in the stomachs. 2. Ingestion of raw soya-bean diet (RSD) or of heated soya-bean diet (HSD) supplemented with trypsin inhibitors induced higher amylase activites in the lower part of the small intestine and caecum as compa...