1. Identification, purification, and characterization of a secretory serine protease in an Indian strain of Leishmania donovani.
- Author
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Choudhury R, Bhaumik SK, De T, and Chakraborti T
- Subjects
- Animals, Cations, Divalent chemistry, Cations, Divalent metabolism, Enzyme Stability, Glycosylation, Humans, Hydrogen-Ion Concentration, India, Isoelectric Point, Metals chemistry, Metals metabolism, Serine Proteinase Inhibitors metabolism, Substrate Specificity, Temperature, Leishmania donovani enzymology, Protozoan Proteins isolation & purification, Protozoan Proteins metabolism, Serine Proteases isolation & purification, Serine Proteases metabolism
- Abstract
An aprotinin sensitive serine protease was identified in the culture supernatant of the Indian strain of Leishmania donovani (MHOM/IN/1983/AG83). The protease was subsequently purified and characterized. The apparent molecular mass of the enzyme was 115 kDa in SDS-PAGE under non-reducing condition, while on reduction it showed a 56 kDa protein band indicating that the protease is a dimeric protein. The purified enzyme was optimally active at the pH and temperature of 7.5 and 28 degrees C, respectively. Assays of thermal stability indicated that the enzyme preserved 59% of activity even after pretreatment at 42 degrees C for 1 h. The purified protease was not glycosylated and its isoelectric pI was 5.0. N-alpha-p-tosyl-L-arginine methylester (TAME) appeared to be relatively better substrate among the commonly used synthetic substrates. The enzyme was inhibited by Ca(2+) and Mn(2+), but activated by Zn(2+). The protease could play important role(s) in the pathogenesis of visceral leishmaniasis or kala-azar.
- Published
- 2009
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