PROPERTIES OF MEMBRANE‐BOUND HEXOKINASE IN RAT BRAIN

Abstract

Abstract— —‐(1) The total hexokinase activity present in the mitochondrial fraction can be solubilized completely by incubation with salt and Triton X‐100. This activity cannot be entirely released by washing with sucrose or by freezing and thawing. (2) A part of the particle bound hexokinase exists in a latent form. The latent form is apparent after incubation with high salt concentrations, detergents or by freezing and thawing. (3) Solubilization of membrane bound hexokinase is pH‐dependent. Incubation in salt solutions increases the specific activity ten‐fold. The salt concentration and pH are con‐current. At pH 7.0 part of the hexokinase is solubilized. The lower the pH the less salt is required to release the same amount of activity. (4) Triton X‐100 solubilizes particle‐bound hexokinase, but to a less extent than salts. The activation of hexokinase is greater with Triton X‐100 than with salt. (5) The possible nature of the bonds between hexokinase and mitochondrial membranes is discussed.