Previous work from this laboratory has shown that the spectral and functional properties of a prokaryotic xanthine dehydrogenase fromComamonas acidovoransshow some similarities to those of the well-characterized eukaryotic enzymes isolated from bovine milk and from chicken liver [Xiang, Q. & Edmondson, . (1996) Biochemistry35, 5441–5450]. Therefore, this system was chosen to study the factors involved in the expression of functional recombinant enzyme in Escherichia colito provide insights into the assembly of the functional Mo-pyranopterin center
