Kinetic Studies Of Erythrocyte Pyruvate Kinase Deficiency

Kinetic studies of erythrocyte pyruvate kinase deficiency Objective:To study the kinetic parameters characterizations and explore the hemolytic mechanism in erythrocyte pyruvate kinase deficiency. Methods:Unconfident Pk deficiency subjects from associate hospitals of Kunming Medical College.PK activity,thermostability, PEP kinetics, ATP inhibition and optimum pH were measured by ICSH recommended methods to confirm deficient in PK.The contents of Na⁺,K⁺,Ca²⁺,Mg²⁺ in erythrocyte PK deficiency were quatitated by inductively coupled plasma atomic emission spectrometry.Results: There were low substrate affinity,thermal instability, alteration of optimum pH and were easily inhibited by ATP in PK-deficient erythrocytes.The contents of Na⁺ were increased while K⁺ decreased were quatitated by ICP-AES as compared the normal erythrocytes. Conclusions: low substrate affinity,thermal instability,product inhibition of PK by ATP and optimum pH appear to play major roles in causing defective enzyme function. Another factor for PK deficiency brought ATP decreasing and change the equilibrium between Na⁺ and K⁺ that reduce the deformation of erythrocytes were the causes of chronic haemolytic anaemia.