HARDNESS CONTROLLED ENZYMES AND ELECTRONEGATIVITY CONTROLLED ENZYMES - ROLE OF AN ABSOLUTE HARDNESS-ELECTRONEGATIVITY (ETA-CHI) ACTIVITY DIAGRAM AS A COORDINATE FOR BIOLOGICAL-ACTIVITIES

We found that absolute hardness-absolute electronegativity (eta-chi) a ctivity diagrams play an important role as a new coordinate of bioacti vity in structure-activity relationships. In this paper, the eta-chi a ctivity diagram, focusing on the molecular mechanism of bioactive comp ounds is used to discuss two major problems. First, the potency of bio activities for xenobiotics such as polychlorinated dibenzo-p-dioxins ( PCDDs) 3 and polychlorinated biphenyls (PCBs) 4, were found to be stro ngly related to their absolute hardness (eta). Second, the antibacteri al activity of new quinolones such as norfloxacin I and enoxacin 2, wa s found to be strongly related to their absolute electronegativity (ch i) These findings predict at least two chemical properties for a hardn ess-controlled or electronegativity-controlled enzyme.