Phospholipid polar head specificity of D-3-hydroxybutyrate dehydrogenase activation studied by new synthetic phospholipids and analogues.

D-3-hydroxybutyrate dehydrogenase, an inner-mitochondrial enzyme responsible for the interconversion of two ketone bodies, is a well known phospholipid dependent enzyme. Newly synthesized phospholipid analogues were used to study the structural requirement for lipid activation of the purified enzyme. A positive charge on the polar head is required but must be at the surface of lipid vesicles. In contrast the maximum velocity and the Michaelis constant values are not strongly dependent on the nature of the zwitterionic phospholipid polar head.