Regulatory characteristics of phospho enolpyruvate carboxylase from the extreme thermophile, Thermus aquaticus

Abstract

Phospho enolpyruvate carboxylase from the extreme thermophilic bacterium, Thermus aquaticus YT-1, exhibits a virtually absolute requirement for acetyl CoA and there is strong positive cooperativity in the interaction of this activator with the enzyme. Several tricarboxylic acid cycle intermediates inhibit the enzyme. These findings suggest an anaplerotic role for the enzyme and an allosteric modulation of its activity by acetyl CoA and tricarboxylic acid cycle intermediates.