title: Defective erythrocyte pyruvate kinase.
abstract: A defective pyruvate kinase (EC 2.7.1.40) is described. The abnormal PK is characterized by a shift in the R in equilibrium T equilibrium to the T-state. The Ko.5 for the substrate phosphoenol pyruvate is about 6 times higher than for the normal enzyme, while the KM value for the positive effector Fru-1, 6-P2 is increased. In agreement with a shift to the T-state is the increased affinity of the abnormal enzyme for the negative effectors ATP and alanine. The results are discussed in relation to other abnormal pyruvate kinases.
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000328:Adult; D000409:Alanine / Q000494:pharmacology; D002239:Carbohydrate Metabolism, Inborn Errors / Q000201:enzymology*; D004912:Erythrocytes / Q000201:enzymology*; D005636:Fructosephosphates / Q000494:pharmacology; D006598:Hexosediphosphates / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008297:Male; D010728:Phosphoenolpyruvate / Q000494:pharmacology; D011770:Pyruvate Kinase / Q000097:blood* / Q000378:metabolism
chemical_list: D005636:Fructosephosphates; D006598:Hexosediphosphates; D010728:Phosphoenolpyruvate; D000255:Adenosine Triphosphate; D011770:Pyruvate Kinase; D000409:Alanine