title: Kinetic properties of triose-phosphate isomerase from Trypanosoma brucei brucei. A comparison with the rabbit muscle and yeast enzymes.
abstract: The kinetic properties of Trypanosoma brucei brucei triose-phosphate isomerase are compared with those of the commercially available rabbit muscle and yeast enzymes and with published data on the chicken muscle enzyme. With glyceraldehyde 3-phosphate as substrate Km = 0.25 +/- 0.05 mM and kcat = 3.7 X 10(5) min-1. With dihydroxyacetone phosphate as substrate Km = 1.2 +/- 0.1 mM and kcat = 6.5 X 10(4) min-1. The pH dependence of Km and Vmax at 0.1 M ionic strength is in agreement with the results published for the yeast and chicken muscle enzymes. At ionic strength below 0.05 M the effect of a charged group specific for the trypanosomal enzyme and absent from the yeast and rabbit muscle enzymes becomes detectable. This effect significantly increases Km whereas Vmax becomes slightly higher. Trypanosomal triose-phosphate isomerase is inhibited by sulphate, phosphate and arsenate ions, by 2-phosphoglycolate and a number of documented inhibitors in the same concentration range as are the other triose-phosphate isomerases. The trypanocidal drug, Suramin inhibits T. brucei and rabbit muscle triose-phosphate isomerase to the same extent while leaving the yeast enzyme relatively unaffected.
authors.affiliation: International Institute of Cellular and Molecular Pathology, Research Unit for Tropical Diseases, Brussels, Belgium.
authors.forename: A M
authors.initials: AM
authors.lastname: Lambeir
authors.forename: F R
authors.initials: FR
authors.lastname: Opperdoes
authors.forename: R K
authors.initials: RK
authors.lastname: Wierenga
mesh_terms: D000818:Animals; D001665:Binding Sites; D002238:Carbohydrate Epimerases / Q000378:metabolism*; D002645:Chickens; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008433:Mathematics; D009132:Muscles / Q000201:enzymology*; D011817:Rabbits; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D013498:Suramin / Q000494:pharmacology; D014305:Triose-Phosphate Isomerase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000201:enzymology*
chemical_list: D013498:Suramin; D002238:Carbohydrate Epimerases; D014305:Triose-Phosphate Isomerase