TARGETING PURINES
Purines are essential to many life processes. These molecules have a double ring structure. The rings are heterocyclic being composed of both carbon and nitrogen. Their nitrogen atoms are vulnerable to reaction with chlorine dioxide. [73a] Examples of important biologic purines are xanthine, hypoxanthine, inosine, guanine and adenine. Guanine and adenine are essential components of DNA and RNA necessary for all genetic functions and for all protein syntheses. Adenine is an essential component of the cofactors NADH, NADPH, FAD and ATP, necessary for many metabolic functions including oxidation-reduction and energy metabolism. Any purines lost by chlorine dioxide exposure can be readily replaced by host cells. [74a] Plasmodia and other apicomplexae are uniquely vulnerable to purine deficiency as they lack the enzymes necessary to produce purines for themselves [75a,75b,75c]. Instead these must be scavenged from host cells and imported across the plasma membranes of the parasite cells.
[76a-76i] Drugs are under development to inhibit purine utilization by Plasmodia and are already showing signs of success. [77a-77g] Temporarily destroying some of the purines in the blood as should occur upon brief exposure to chlorine dioxide in vivo is probably an additional stress that Plasmodia cannot tolerate.