Purification and Characterization of Three Proteinase Inhibitors from Canavalia lineata Seeds

概要

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Three proteinase inhibitors (CLTI-I, -II, and -III) were purified from the seeds of Canavalia lineata by DEAE-Toyopearl, hydroxyapatite, and anhydrotrypsin-Sepharose column chromatographies. All the inhibitors bound to trypsin at a 1 : 1 molar ratio and inhibited the enzyme with dissociation constants of 3-7×10^<-9>M. They also showed the inhibitory activities on chymotrypsin. CLTI-I and -II had an identical M_r of 8000 and very close isoelectric points (4. 57 and 4. 50), and existed mainly as trimers under physiological conditions. The high content of half-cystine residues and the high stability to pH and heat have suggested that these are Bowman-Birk type inhibitors. On the other hand, CLTI-III, with an M_r of 20, 500 was classified as a Kunitz (soybean) family inhibitor on the basis of the amino acid composition as well as the homology of its N-terminal 17 residues to other Kunitz inhibitors.
社団法人日本農芸化学会の論文
1994-02-23