The Molecular Basis of Muscle Phosphofructokinase Deficiency

Abstract

Experiments were designed to test the hypothesis that human erythrocyte phosphofructokinase (PFK) is composed of nonidentical subunits (M and R) while muscle PFK is composed of M subunits only. When erythrocyte PFK was dissociated into inactive subunits at pH 5.3, the R subunit could be precipitated by a specific antibody, and the reassociated enzyme at pH 8.0 had the chromatographic and immunologic characteristics of muscle PFK. When dissociated erythrocyte PFK was treated with antiserum against muscle PFK and reassociated, the resultant enzyme no longer contained the M-type antigen. The chromatographic methods did not distinguish between native erythrocyte PFK and PFK from which the subunits had been removed. The results support the original hypothesis and provide a basis for explaining muscle PFK deficiency as a genetic lack of the M subunit.