title: The human pathogen Leishmania donovani secretes a histidine acid phosphatase activity that is resistant to proteolytic degradation.
abstract: Promastigotes of all pathogenic Leishmania species secrete acid phosphatase (SAcP) activity during their growth in vitro. It has been suggested that this enzyme may play a role in the survival of the parasite within its sandfly-vector host. To carry out such functions, SAcP would have to be relatively resistant to endogenous sandfly gut-proteases. Therefore, the current study was undertaken to ascertain whether L. donovani SAcP activity was affected by treatment with various proteases. Native L. donovani SAcP was treated with a variety of serine-, thiol-, metallo- and mixed-proteases and subsequently assayed for enzymatic activity. Of the eleven proteases tested, only bromelain and subtilisin treatments caused a pronounced reduction in SAcP activity. Treatment of SAcP with seven out of the remaining nine proteases, resulted in an overall enhancement in SAcP enzymatic activity ranging from approximately 10% (e.g. with trypsin) to > or = 90% (e.g. with ficin). The resistance of the Leishmania SAcP to various proteases may prolong its functional life within the sandfly gut and help to facilitate parasite infection in this host.
authors.affiliation: Cell Biology Section, Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892-0425, USA.
authors.forename: Manju B
authors.initials: MB
authors.lastname: Joshi
authors.forename: David J
authors.initials: DJ
authors.lastname: Mallinson
authors.forename: Dennis M
authors.initials: DM
authors.lastname: Dwyer
mesh_terms: D000818:Animals; D010450:Endopeptidases / Q000378:metabolism; D006801:Humans; D006867:Hydrolases / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D007893:Leishmania donovani / Q000201:enzymology* / Q000472:pathogenicity*; D013379:Substrate Specificity
chemical_list: D006867:Hydrolases; D010450:Endopeptidases; C400721:13 kDa phosphoamidase