Biochemical properties of Candida parapsilosis ecto-5'-nucleotidase and the possible role of adenosine in macrophage interaction.
Candida parapsilosis is considered to be an emerging fungal pathogen because it is associated with an increasing range of infections. In this work, we biochemically characterized ecto-5'-nucleotidase activity on the surface of living, intact C. parapsilosis cells. At a pH of 4.5, intact cells were able to hydrolyze 5'-AMP at a rate of 52.44 ± 7.01 nmol Pi h(-1) 10(-7) cells. 5'-AMP, 5'-IMP and 5'-UMP were hydrolyzed at similar rates, whereas 5'-GMP and 5'-CMP hydrolyzed at lower rates. Enzyme activity was increased by about 42% with addition of Mg(2+) or Ca(2+), and the optimum pH was in the acidic range. An inhibitor of phosphatase activities, sodium orthovanadate, showed no effect on AMP hydrolysis; however, as expected, ammonium molybdate, a classical nucleotidase inhibitor, inhibited the activity in a dose-dependent manner. The results indicated that the existence of an ecto-5'-nucleotidase could play a role in the control of extracellular nucleotide concentrations.
Instituto de Bioquímica Médica, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro, UFRJ, Cidade Universitária, Rio de Janeiro, RJ, Brazil.
Thais
T
Russo-Abrahão
Daniela
D
Cosentino-Gomes
Marta T
MT
Gomes
Daniela S
DS
Alviano
Celuta S
CS
Alviano
Angela H
AH
Lopes
José Roberto
JR
Meyer-Fernandes
D015720:5'-Nucleotidase / Q000378:metabolism*; D000241:Adenosine / Q000378:metabolism*; D000249:Adenosine Monophosphate / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002175:Candida / Q000201:enzymology* / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D003568:Cytidine Monophosphate / Q000378:metabolism; D020536:Enzyme Activators / Q000378:metabolism; D006157:Guanosine Monophosphate / Q000378:metabolism; D054884:Host-Pathogen Interactions; D006863:Hydrogen-Ion Concentration; D007291:Inosine Monophosphate / Q000378:metabolism; D007700:Kinetics; D008274:Magnesium / Q000378:metabolism; D014542:Uridine Monophosphate / Q000378:metabolism
D002413:Cations, Divalent; D020536:Enzyme Activators; D007291:Inosine Monophosphate; D000249:Adenosine Monophosphate; D006157:Guanosine Monophosphate; D014542:Uridine Monophosphate; D015720:5'-Nucleotidase; D003568:Cytidine Monophosphate; D008274:Magnesium; D000241:Adenosine; D002118:Calcium