Inhibitory and restorative effects of adenine nucleotides on rickettsial adsorption and hemolysis.

The adenine nucleotides, adenosine diphosphate, adenosine triphosphate, (ATP), and the methylene-bridge analogues are inhibitors of rickettsial adsorption to and the hemolysis of sheep erythrocytes. Other nucleotides, adenosine monophosphate, cyclic adenosine monophosphate, cytosine triphosphate, and guanosine triphosphate, are without effect. Adsorption and hemolysis require the generation of energy by the rickettsiae which is usually derived from glutamate. When the generation of energy from the metabolism of glutamate is inhibited by arsenite or cyanide, the addition of ATP can supply the energy to restore hemolysis. However, in the presence of the uncouplers, ATP can not restore hemolysis. Even when functioning in a restorative role, ATP still has its inhibitory properties. These results suggest that a high-energy intermediate (X approximately I), rather than ATP itself, is the energy source. The interactions of inhibitory nucleotides suggest that these compounds share a common transport system.