Entamoeba histolyticaHM1:IMSS: Hemoglobin-Degrading Neutral Cysteine Proteases

• Published in: Experimental parasitology 1998-05, Vol.89 (1), p.71-77
• Main Authors: Serrano-Luna, José de Jesús, Negrete, Erasmo, Reyes, Magda, de la Garza, Mireya
• Format: Article
• Language: English
• ISSN: 0014-4894; 1090-2449
• DOI: 10.1006/expr.1998.4258

Serrano-Luna, J. de J., Negrete, E., Reyes, M., and de la Garza, M. 1998.Entamoeba histolyticaHM1:IMSS: Hemoglobin-degrading neutral cysteine proteases.Experimental Parasitology89,71–77.Entamoeba histolyticaHM1:IMSS trophozoites were able to utilize human hemoglobin but not hemin as a sole iron source to growin vitro. Proteases from crude extracts ofE. histolyticadegraded human, porcine, and bovine hemoglobins at pH 7.0. These proteolytic activities were found by electrophoresis in SDS-polyacrylamide gels copolymerized with hemoglobin, with apparent molecular weights of 116, 82, and 21 kDa, the 82-kDa protein being the most active protease against this substrate. The proteases were classified in the cysteine group since the activities were inhibited by l-trans-epoxysuccinylleucylamido (4-guanidino)butane,p-hydroxymercuribenzoate, iodoacetate, andN-ethylmaleimide and activated with dithiothreitol. Other pathogenic strains ofE. histolyticashowed the same pattern of hemoglobinases. These hemoglobin-degrading proteases could be playing an important role in iron acquisition by E. histolytica.