Selective inhibition of lignoceroyl-CoA synthetase by adenosine 5'-alkylphosphates

Structural analogs of adenosine 5'-acylphosphates, which are intermediates of the reaction catalyzed by acyl-CoA synthetases, were synthesized by condensing primary alcohols with AMP to examine the inhibitory effects on the lignoceroyl-CoA and palmitoyl-CoA synthetase activities. Hexadecyl, octadecyl, eicosyl, docosyl and tetracosyl esters of AMP were remarkably potent inhibitors of the lignoceroyl-CoA formation. On the other hand, the eicosyl, docosyl or tetracosyl esters of AMP did not behave as significant inhibitors of the palmitoyl-CoA formation at the concentration at which the two other shorter chain analogs were effective. Namely, these longer alkyl esters of AMP have selective inhibitory effects on the lignoceroyl-CoA synthetase activity. The Ki value of adenosine 5'-tetracosylphosphate, the most potent inhibitor, was about one tenth lower than the Km value for the substrate lignoceric acid. Furthermore, the results support the notion that lignoceroyl-CoA synthetase is distinct from palmitoyl-CoA synthetase.