title: Ribonuclease activity of Entamoeba histolytica.
abstract: Ribonuclease activity of Entamoeba histolytica was purified 65-fold by calcium phosphate gel, ammonium sulphate and acetone treatments. The enzyme was inhibited by metal ions, like Mg-2+, Mn-2+, Co-2+ and Ca-2+. Metal chelating and sulphydryl agents showed no effect. EDTA and alpha, a'-dipyridyl reversed the inhibition produced by Mg-2+, Mn-2+ and Fe-2+. Various sodium salts had negligible effect on the enzyme; however, sodium chloride activated the enzyme slightly. Amoebicidal drugs like enterovioform and chloroquine phosphate inhibited the enzyme completely, while emetine showed marked inhibitory effect. Neomycin exhibited a slight stimulatory action on this enzyme.
mesh_terms: D000563:Amebicides / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002614:Chelating Agents / Q000494:pharmacology; D004748:Entamoeba histolytica / Q000201:enzymology*; D006863:Hydrogen-Ion Concentration; D008670:Metals / Q000494:pharmacology; D012260:Ribonucleases / Q000037:antagonists & inhibitors / Q000302:isolation & purification; D013439:Sulfhydryl Reagents / Q000494:pharmacology
chemical_list: D000563:Amebicides; D000900:Anti-Bacterial Agents; D002614:Chelating Agents; D008670:Metals; D013439:Sulfhydryl Reagents; D012260:Ribonucleases