SPECIFIC INCORPORATION OF MOLYBDOPTERIN IN XANTHINE DEHYDROGENASE OF PSEUDOMONAS-AERUGINOSA

All known molybdoenzymes other than nitrogenase contain the metal in a ssociation with molybdopterin or one of its dinucleotide variants. All eukaryotic molybdoproteins have been found to contain only molybdopte rin, whereas the majority of bacterial enzymes contain one or another of the dinucleotides of molybdopterin. In contrast, xanthine dehydroge nase from Pseudomonas aeruginosa contains molybdopterin rather than a dinucleotide. To examine whether P. aeruginosa contains any dinucleoti de of molybdopterin, cells were subjected to an analytical procedure w hich converts molybdopterin variants to the highly fluorescent Form A derivatives. The results showed that P. aeruginosa cells do contain mo lybdopterin guanine dinucleotide. The same procedure showed that rat l iver does not contain any of the dinucleotides of molybdopterin. (C) 1 994 Academic Press, Inc.