title: Characterization of Trypanosoma cruzi hexokinase.
abstract: Properties of hexokinase (EC 2.7.1.1) from Trypanosoma cruzi epimastigote forms (Tulahuen strain) were studied and compared with enzymes from other sources. The enzyme activity was 37 units g-1 of wet cells (1.2 units mg-1 protein). Hexokinase showed Km values for glucose and ATP of 0.09 and 0.4 mM, respectively. The enzyme reacted with other nucleotides too. N-Acetylglucosamine was a competitive inhibitor with respect to glucose (Ki = 0.3 mM). ADP inhibited the enzyme competitively with respect to ATP (Ki = 1.5 mM) and noncompetitively with respect to glucose (Ki = 7 mM). The enzyme was markedly inhibited by 5-thioglucose, its Ki value was 0.4 mM. Hexokinase activity was not affected by glucose 6-phosphate.
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000818:Animals; D006593:Hexokinase / Q000032:analysis* / Q000037:antagonists & inhibitors; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008928:Mitochondria / Q000201:enzymology; D011506:Proteins / Q000378:metabolism; D013347:Subcellular Fractions / Q000201:enzymology; D013379:Substrate Specificity; D014349:Trypanosoma cruzi / Q000201:enzymology*
chemical_list: D011506:Proteins; D000244:Adenosine Diphosphate; D006593:Hexokinase