A number of animal, plant and bacterial enzymes contain molybdenum. In all cases it appears that the molybdenum is contained within a "molybdenum cofactor," in a distinct structure which is essential for the enzyme's function. The chemical structure of this cofactor has been highly conserved in different organisms. From studies done on several species it is evident that groups of genes mediate the biosynthesis or acquisition of the molybdenum cofactor. The failure of certain master genes to function in genetic mutants can result in the loss of all molybdenum enzyme activities, with drastic consequences for the organisms bearing this defect. Dr. Finnerty's project focuses on an analysis of an important gene for an enzyme containing molybdenum in the fruit fly Drosophila. Drosophila is an organism about which there is a great deal of genetic information available, and it therefore provides a highly favorable model system for investigation of the manner in which molybdenum is housed in enzymes that contain it. In addition to making use of genetic analyses, Dr. Finnerty is carrying out biochemical analyses to provide a comprehensive analysis of the structure and function of molybdenum cofactors in the Drosophila system. Through investigation of this model system, information will be obtained that will be of benefit to the understanding of enzymes bearing the molybdenum cofactor in a variety of organisms.***//