Our long term goals in this research is to thoroughly investigate the rich mechanistic and stereochemical questions associated with the enzymes of aromatic acid matabolism. These enzymes, particularly those constituting the Beta-ketoadipate pathway, are of considerable interest from an intellectual as well as practical standpoint. These studies should shed light on the role of mechanism and stereochemistry in the evolution of these enzymes as they adapted to specific functions and specific substrates. In addition, the biodegradation of aromatics is becoming increasingly important as a potential solution to the problem of polution control. Our specific aims during the funding period will be: (1) A study of the mechanism and stereochemistry of the enzymes of the Beta-ketoadipate pathway from P. putida. (2) The analysis of the reactions of haloprotocatechuates with the P. putida enzymes. (3) A study of the mechanism and stereochemistry of enzymes of A. calcoaceticus, particulary the two enol-lactone hydrolases. (4) An analysis of the Pseudomonas sp B13 enzymes, particularly the specific enzymes responsible halocatechol metabolism. (5) A study of the enzymes from the eukaryote, Trichosporon cutaneum, which appear to have different specificities. We believe that these basic studies should serve as a foundation for the genetic manipulation of microorganisms to meet specific detoxification needs. Furthermore, the studies will increase our mechanistic understanding of these intriguing enzymes.