Cysteine proteinase inhibitors from rabbit skeletal muscle |
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Authors: | M Matsuishi A Okitani Y Hayakawa H Kato |
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Affiliation: | Department of Food Science and Technology, Nippon Veterinary and Zootechnical College, Japan. |
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Abstract: | 1. Two cysteine proteinase inhibitors, I-T (Mr = 29,000) and I-S (Mr = 10,700), were isolated from rabbit skeletal muscle by means of succesive extraction with a neutral buffer solution, precipitation at pH 3.7, acetone fractionation and gel permeation on Sephadex G-75. 2. I-T is a formed trimer of a monomeric inhibitor, I-M (Mr = 10,500), through disulfide bonds. 3. I-S is almost completely stable between pH 3 and 8, while I-M is unstable in the same pH range. 4. I-M acts most effectively towards cathepsins H and L, showing moderate activity towards cathepsin B and only weak activity towards papain. I-S acts most effectively towards cathepsin L, followed by, in decreasing order, cathepsin H, cathepsin B and papain. |
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