title: Isolation and partial characterization of the trypsin inhibitor from the seeds of Brassica oleracea var. sabellica.
abstract: A trypsin inhibitor was extracted from the kale seeds with 0.01 M-HCl, precipitated with ammonium sulphate, and purified by affinity chromatography on immobilized trypsin and ion-exchange chromatography on QAE-Sephadex A-25. The inhibitor, of Mr 8 000, is composed of 64 amino acid residues and contains neither threonine nor methionine. Its isoelectric point is 8.9. In addition to trypsin, the inhibitor acts on subtilopeptidase A and shows a very weak antichymotrypsin activity. The factors modifying the arginine residues inactivate the inhibitor. A modified form of the inhibitor (with a broken reactive site peptide bond) has been isolated in pure form, and its properties were compared with those of the virgin form.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D001120:Arginine; D001665:Binding Sites; D001937:Brassica; D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002621:Chemistry; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D002918:Chymotrypsin / Q000037:antagonists & inhibitors; D007526:Isoelectric Point; D010944:Plants / Q000032:analysis*; D012639:Seeds; D014357:Trypsin / Q000378:metabolism; D014361:Trypsin Inhibitors / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D014361:Trypsin Inhibitors; D001120:Arginine; D002918:Chymotrypsin; D014357:Trypsin