Cocaine is a powerful psycho stimulant and one of the most addictive drugs of abuse. Despite decades of efforts, no effective pharmacological treatments have been developed for cocaine addiction or acute cocaine toxicity. There are two main approaches in developing the anti-cocaine treatments. 1) pharmacodynamic interventions: searching for compounds that inhibit cocaine binding to its targets, which have not resulted in effective drugs yet;2) pharmacokinetic interventions: strategies to limit or reduce the amount of cocaine available to act on its target proteins, such as the development of cocaine binding antibodies and improved cocaine degrading enzymes. The antibodies could be overwhelmed by large doses of cocaine while each enzyme protein can degrade many cocaine molecules. Significant progress has been made in improving the relative slow endogenous human enzymes by specific and random mutagenesis and by computation guided mutagenesis. In addition, a very active bacterial esterase has been cloned that hydrolyzes cocaine faster than any other known enzymes. However, this enzyme has no homology to the human enzymes and introducing this bacterial protein itself in the human body may cause severe immune responses. Therefore, we propose a strategy that takes advantage of the evolution power of nature. We propose to clone the cocaine degrading enzymes from Eloria Noyesi, the main insect pest of coca plants from which cocaine is extracted. These insects ingest large quantity of cocaine in its diet. The blood cocaine level in the feeding larvae is quite low and most of the ingested cocaine is degraded, suggesting the presence of super fast cocaine-degrading enzymes that have evolved to deal with the high cocaine diet. The successful cloning and additional studies of the cocaine degrading enzymes from Eloria should reveal the structural insight and catalytic mechanism of super efficient cocaine hydrolysis, which may provide novel ideas on how to modify and improve the human enzymes. Such ideas, combined with studies from other labs, may lead to further progress in engineering an ideal enzyme. Any significant improvement in the efficiency of the cocaine-degrading enzyme will make a big impact on the efficacy of an enzyme-based treatment of cocaine abuse.
We propose to clone the super efficient cocaine-degrading enzymes from Eloria Noyesi, the main insect pest of coca plant E. coca from which cocaine is extracted. The successful cloning and further studies of these enzymes may reveal the mechanistic insight of super efficient cocaine hydrolysis and thus provide novel ideals to further improve the human enzymes, which may eventually lead to effective and specific treatments for cocaine addiction and toxicity.
