Rhizopuspepsin is an aspartic proteinase from the fungus Rhizopus chinensis. Interest in rhizopuspepsin as a model system for studying active site interactions stems principally from the need to understand interactions which may be exploited in rational drug design. Targets for these therapeutics are renin, which plays a role in hypertension, the HIV proteinase, essential to the HIV life cycle, and a variety of related, secreted Candida yeast aspartic proteinases[1, 2].KeywordsAspartic ProteinaseRational Drug DesignUnique SpecificityPorcine PepsinOklahoma Medical Research FoundationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.