title: A cryptic protease activity from Trypanosoma cruzi revealed by preincubation with kininogen at low temperatures.
abstract: Cysteine proteases have been identified in parasitic protozoa including the causative agent of Chagas' disease Trypanosoma cruzi. T. cruzi lysates subjected to substrate-containing SDS-polyacrylamide gel electrophoresis exhibit major bands of proteolytic activity in the 45-55 kDa molecular mass range (cruzipain activity). Paradoxically, addition of kininogen (a cystatin-like protease inhibitor) to the lysates before electrophoresis results in the appearance of additional bands of proteolytic activity in the 160-190 kDa molecular mass range. This inhibitor-activated protease activity depends upon the reaction conditions and exhibits novel properties. For example, a 24-48 hour preincubation at low temperature (-20 degrees C optimum) greatly enhances the proteolytic activity. The results suggest that a metastable complex forms between kininogen and a cryptic 30 kDa cysteine protease from T. cruzi and that this complex participates in the activation of proteolytic activity.
authors.affiliation: Department of Tropical Medicine, Tulane University School of Public Health and Tropical Medicine, New Orleans, Louisiana 70112, USA. wiser@mailhost.tcs.tulane.edu
authors.forename: M F
authors.initials: MF
authors.lastname: Wiser
authors.forename: J D
authors.initials: JD
authors.lastname: Lonsdale-Eccles
authors.forename: A
authors.initials: A
authors.lastname: D'Alessandro
authors.forename: D J
authors.initials: DJ
authors.lastname: Grab
mesh_terms: D000818:Animals; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005780:Gelatin / Q000378:metabolism; D007700:Kinetics; D007704:Kininogens / Q000378:metabolism* / Q000494:pharmacology; D008970:Molecular Weight; D013696:Temperature; D014349:Trypanosoma cruzi / Q000201:enzymology*
chemical_list: D004791:Enzyme Inhibitors; D007704:Kininogens; D005780:Gelatin; D003546:Cysteine Endopeptidases