The amino acid sequence around the active-site cysteine and histidine residues, and the buried cysteine residues in ficin |
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| Authors: | S. S. Husain and G. Lowe |
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| Affiliation: | The Dyson Perrins Laboratory, University of Oxford, Oxford OX1 3QY, U.K. |
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| Abstract: | Ficin that had been prepared from the latex of Ficus glabrata by salt fractionation and chromatography on carboxymethylcellulose was completely and irreversibly inhibited with 1,3-dibromo[2-(14)C]acetone and then treated with N-(4-dimethylamino-3,5-dinitrophenyl)maleimide in 6m-guanidinium chloride. After reduction and carboxymethylation of the labelled protein, it was digested with trypsin and alpha-chymotrypsin. Two radioactive peptides and two coloured peptides were isolated chromatographically and their sequences determined. The radioactive peptides revealed the amino acid sequences around the active-site cysteine and histidine residues and showed a high degree of homology with the omino acid sequence around the active-site cysteine and histidine residues in papain. The coloured peptides allowed the amino acid sequence around the buried cysteine residue in ficin to be determined. |
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