Purification and Properties of Pig‐Heart Hexokinase

Abstract

Hexokinase has been purified from pig heart to a specific activity of 80 units/mg. The enzyme has an s 20 of 5.11 ± 0.15 S and a molecular weight of 97000. Dodecylsulphate‐polyacrylamide electrophoresis and maleylation of the enzyme each suggest that it contains a single polypeptide chain. Amino‐acid analysis reveals similarities between the compositions of heart and brain hexokinases. Steady‐state kinetic investigations at sub‐optimal substrate concentrations are consistent with a mechanism in which at least one of the substrates is in equilibrium with its enzyme · substrate complex.