Aminopeptidases from Plasmodium falciparum, Plasmodium chabaudi chabaudi and Plasmodium berghei |
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Authors: | G. PAUL CURLEY SUSAN M. O'DONOVAN JOHN MCNALLY MARGARET MULLALLY HELEN O'HARA ALICE TROY SUE-ANN O'CALLAGHAN JOHN P. DALTON |
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Affiliation: | School of Biological Sciences, Dublin City University, Glasnevin, Dublin 9, Republic of Ireland |
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Abstract: | ABSTRACT. Using fluorogenic substrates and polyacrylamide gels we detected in cell-free extracts of Plasmodium falciparum, Plasmodium chabaudi chabaudi and Plasmodium berghei only a single aminopeptidase. A comparative study of the aminopeptidase activity in each extract revealed that the enzymes have similar specificities and kinetics, a near-neutral pH optima of 7.2 and are moderately thermophilic. Each has an apparent molecular weight of 80,000 ± 10,000, determined by high performance liquid chromatography on a calibrated SW500 column. Whilst the P. c. chabaudi and P. berghei activity co-migrate in native polyacrylamide gels, that of P. falciparum migrates more slowly. The three enzymes can be selectively inhibited by ortho -phenanthroline and are thus metallo-aminopeptidases; however, in contrast to other aminopeptidases the metal co-factor does not appear to be Zn2+. |
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Keywords: | Malaria metallopeptidases aminopeptidases |
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