ON THE EVOLUTION OF ARGINASES AND RELATED ENZYMES

Sequence analysis of the arginase/agmatine ureohydrolase family, impor tant enzymes in arginine/agmatine metabolism and the urea cycle, revea ls the similarity of arginases to formiminoglutamate hydrolase (hutG) in Klebsiella aerogenes and to a previously unidentified open reading frame adjacent to the HMf locus of the archaebacterium Methanothermus fervidus. The gene structure and distribution of these homologous prot eins across primary kingdoms suggest that this family is another examp le of a primordial enzyme possibly present in the universal common anc estor and that can be used as phylogenetic marker.