Self-proteolysis of the cysteine proteinase, cruzipain, from Trypanosoma cruzi gives a major fragment corresponding to its carboxy-terminal domain.
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Hellman U, Wernstedt C, Cazzulo JJ
Self-proteolysis of the cysteine proteinase, cruzipain, from Trypanosoma cruzi gives a major fragment corresponding to its carboxy-terminal domain.
Mol Biochem Parasitol. 1991 Jan;44(1):15-21.
- PubMed ID
- 2011151 [ View in PubMed]
- Abstract
The major cysteine proteinase (cruzipain) purified from Trypanosoma cruzi epimastigotes catalyzes its own degradation in the presence of beta-mercaptoethanol, at 56 degrees C and pH 6. The reaction is affected by the same inhibitors which inhibit the azocaseinase activity, and yields a major 25-kDa fragment, which contains carbohydrate, few, if any, aromatic amino acids, and presents a proline-rich N-terminus (GPGPXPEP...), in addition to a number of small peptides, which can be isolated by reversed-phase HPLC, but are lost during electrophoresis. The results, together with recently published evidence of Mottram et al. and Eakin et al., are compatible with a structure for cruzipain consisting of a conventional cysteine proteinase moiety, linked to a long C-terminal extension including the 25-kDa fragment, which would contain a high proportion of the carbohydrate and the proline residues present in the original 60-kDa molecule.