Isolation and partial characterization of a trypsin inhibitor from wheat endosperm.

Trypsin inhibitors were isolated from wheat endosperm, and a major inhibitor (wheat endosperm trypsin inhibitor-I, WETI-I) was purified by ion-exchange chromatographies on CM-Sephadex and SP-Sephadex, gel filtration on Sephadex G-75 and chromatofocusing on Polybuffer exchanger PBE 94. This inhibitor was a polypeptide composed solely of amino acids, and its pI value was 9.35. It was found to be homogeneous in gel electrophoresis and velocity sedimentation. It showed strong inhibition on bovine trypsin but weak inhibition on bovine alpha-chymotrypsin. The molecular weight of the inhibitor was approximately 7,800 as judged from SDS-gel electrophoresis. This finding, along with the trypsin inhibition data, suggested that the inhibitor bound trypsin in the molar ratio of 1:1. Certain other properties of the inhibitor, including amino acid composition and UV spectral characteristics are presented.

[1]  T. Mitsunaga,et al.  Isolation and characterization of trypsin inhibitors from wheat germ. , 1979, Journal of nutritional science and vitaminology.

[2]  M. Tashiro,et al.  Purification and characterization of a trypsin inhibitor from rice bran. , 1979, Journal of nutritional science and vitaminology.

[3]  M. Tashiro,et al.  Occurrence of a trypsin inhibitor in eggplant exocarps. , 1975, Journal of nutritional science and vitaminology.

[4]  V. Silano,et al.  Comparison of wheat albumin inhibitors of α-amylase and trypsin , 1974 .

[5]  T. Mistunaga.  Some properties of protease inhibitors in wheat grain. , 1974, Journal of nutritional science and vitaminology.

[6]  T. Kiyoara,et al.  Chemical and physicochemical characterization of two different types of proteinase inhibitors (inhibitors II-a and II-b) from potatoes. , 1972, Journal of biochemistry.

[7]  E. Shaw,et al.  [2] Titration of trypsin, plasmin, and thrombin with p-nitrophenyl p′-guanidinobenzoate HCl☆ , 1970 .

[8]  K. Weber,et al.  The reliability of molecular weight determinations by dodecyl sulfate-polyacrylamide gel electrophoresis. , 1969, The Journal of biological chemistry.

[9]  J V Maizel,et al.  Molecular weight estimation of polypeptide chains by electrophoresis in SDS-polyacrylamide gels. , 1967, Biochemical and biophysical research communications.

[10]  G. Shyamala,et al.  THE ISOLATION AND PURIFICATION OF A TRYPSIN INHIBITOR FROM WHOLEWHEAT FLOUR. , 1964, Canadian journal of biochemistry.

[11]  U. Lewis,et al.  Disk Electrophoresis of Basic Proteins and Peptides on Polyacrylamide Gels , 1962, Nature.

[12]  William W. Cohen,et al.  The preparation and properties of two new chromogenic substrates of trypsin. , 1961, Archives of biochemistry and biophysics.

[13]  G. Shyamala,et al.  Trypsin Inhibitor in Wholewheat Flour , 1961, Nature.

[14]  O. H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[15]  T. Goodwin,et al.  The spectrophotometric determination of tyrosine and tryptophan in proteins. , 1946, The Biochemical journal.