Investigations of the Kinetics of Red Cell Pyruvate Kinase in Normal Individuals and in a Patient with Pyruvate Kinase Deficiency

Abstract

SINCE the first report by Tanaka et al.¹ of non-spherocytic haemolytic anaemia due to pyruvate kinase (PK) deficiency, about twenty further cases have been reported. In patients with this type of haemolytic anaemia, determinations of PK give decreased, but not totally absent, enzyme activities. The remaining activity amounts to 5–20 per cent of the normal. Waller² first posed the question as to whether there was any real lack of enzyme or whether the disease was due to a structurally changed enzyme protein with decreased affinity to the substrate. He reported two cases where the Michaelis constant of the PK towards phosphoenolpyruvate (PEP) was significantly higher in erythrocytes of patients than in normal human beings.