Site-site interaction in the lipid activation of β-hydroxybutyrate dehydrogenase

Abstract

Kinetic data for the activation of the β-hydroxybutyrate dehydrogenase by long-chain lecithins [(1979) Biochemistry 18, 2420–2429; (1983) J. Biol. Chem. 258, 208–214] are analyzed. A previous kinetic model [(1982) Biochemistry 21, 3899–3908] is shown not to apply. Instead, the use of a two-site Adair equation points to a strongly cooperative interaction between the lecithin binding sites (ΔG, −2.8 kcal/mol).