title: On the acid phosphatase isoenzymes existing in American Leishmania promastigotes.
abstract: 1. Two partially purified acid phosphatase activities present in American Leishmania promastigote homogenates were characterized by biochemical methods. 2. One isoenzyme acts preferentially on p-nitrophenyl phosphate, is strongly inhibited by 30 mM alloxan, citrate, maleate, malonate and succinate, and strongly stimulated by 3 mM spermine. Its pI is 4.8. 3. The other isoenzyme acts preferentially on beta-glycerophosphate and is resistant to 30 mM alloxan, citrate, maleate, malonate and succinate and also to 3 mM spermine. Its pI is 5.7. 4. Both acid phosphatase isoenzymes have an optimum pH of 5.2, are tartrate-sensitive and strongly membrane-bound, as shown by differential centrifugation and density gradient equilibration. 5. Both isoenzymes were separated by using homogenates prepared in 2% Triton X-100, differential centrifugation, Sepharose 4B/CL-4B gel filtration, ion exchange chromatography and electrofocusing. After this procedure, they were still contaminated with several different proteins. 6. Purification was around 150-fold, with a 32% yield. 7. When these acid phosphatase activities were measured in total homogenates from 12 different Leishmania isolates, p-nitrophenyl phosphatase specific activity values were quite close; beta-glycerophosphatase-specific activity had around a 2-fold variation. 8. This variation was independent from taxonomic classification or infectivity of susceptible hosts.
authors.affiliation: Instituto de Biomedicina, Caracas, Venezuela.
authors.forename: J L
authors.initials: JL
authors.lastname: Avila
authors.forename: D
authors.initials: D
authors.lastname: Hernández-Morales
authors.forename: M A
authors.initials: MA
authors.lastname: Polegre
authors.forename: J
authors.initials: J
authors.lastname: Convit
mesh_terms: D000135:Acid Phosphatase / Q000302:isolation & purification / Q000378:metabolism*; D000496:Alloxan / Q000494:pharmacology; D000818:Animals; D002845:Chromatography; D002951:Citrates / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007525:Isoelectric Focusing; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D007891:Leishmania / Q000201:enzymology*; D007892:Leishmania braziliensis / Q000201:enzymology*; D007894:Leishmania mexicana / Q000201:enzymology*; D011506:Proteins / Q000494:pharmacology; D012995:Solubility; D013096:Spermine / Q000494:pharmacology; D013379:Substrate Specificity
chemical_list: D002951:Citrates; D007527:Isoenzymes; D011506:Proteins; D013096:Spermine; D000496:Alloxan; D000135:Acid Phosphatase