A comparison of substrate-dependent fatty acyl-CoA synthetase activities and ATP hydrolysis in membrane pellets from normal and trembler mouse sciatic nerves

Abstract

Acyl-CoA synthetase activity was investigated in membrane fractions from normal and Trembler mouse sciatic nerves. Stearoyl-CoA synthesis in the Trembler assays was always about twice that observed in the control experiments under various conditions of CoA and ATP concentrations. In experiments using varying concentrations of fatty acid, the activation of stearate was very low in both systems (normal and Trembler), up to a substrate concentration of 20 mM, suggesting that fatty acid micelles are required for full activity. ATP, at concentrations of up to 1 mM, was totally (Trembler) or partially (control) hydrolyzed within 15 min, resulting in an apparently lower ligase activity in the mutant than in the control when an ATP-regenerating system was not added. The activation of saturated fatty acids decreased with increasing chain length. However, lignoceroyl-CoA formation was detected in the mutant but not in the control.