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A study of trypsin inhibitors

1960; Wiley; Volume: 39; Issue: 1 Linguagem: Inglês

10.1002/macp.1960.020390112

0025-116X

Von B. Jirgensons, Tokuji Ikenaka, V. Gorguraki,

Protein Interaction Studies and Fluorescence Analysis

Abstract The optical rotatory properties, amino acid composition, chromatographic fractionation, and enzymic inhibition activity of several trypsin inhibitors were investigated. The homogeneity of these proteins was tested by free boundary electrophoresis and sedimentation in the ultracentrifuge. A crude fraction of lima bean trypsin inhibitor was fractionated by diethylaminoethyl cellulose ion exchange chromatography into several subfractions. It was attempted to correlate the inhibiting capacity of the proteins with their chemical composition and gross configuration (conformation) of the macromolecules. On the basis of the optical rotatory dispersion results, it was concluded that the polypeptide chain conformation of the soybean trypsin inhibitor differs considerably from that of the two major inhibiting components found in the lima beans. Also it was found that ovomucoid exhibits an unusual decrease in levorotation upon denaturation in alkali, and that its dispersion constant differs strongly from the respective constants of the bean proteins. It was concluded that the inhibiting power is due neither to a specific gross configuration nor unique amino acid composition of the inhibitors, but that only short segments of the chains of both the trypsin and inhibitor are essential for the interaction that leads to inactivation of the enzyme.