ALCOHOL-DEHYDROGENASE OF CLASS-III - CONSISTENT PATTERNS OF STRUCTURAL AND FUNCTIONAL CONSERVATION IN RELATION TO CLASS-I AND OTHER PROTEINS

Class III alcohol dehydrogenase from the lizard Uromastix hardwickii h as been characterized, This non-mammalian, gnathostomatous vertebrate class III form allows correlations of structures and functions of this class, the traditional class I alcohol dehydrogenase, and other well- studied proteins, Catalytically, results show similar recoveries and a ctivities of all vertebrate class III forms independent of source, sim ilar activities also in invertebrates but in lower amounts, and consid erably higher specific activities in microorganisms, Structurally, var iability patterns are consistent throughout the vertebrate system with a ratio in accepted point mutations versus class I of 0.4. This ratio between different classes of a zinc enzyme is comparable to that betw een different heme proteins (cytochrome c and myoglobin), suggesting d efined but non-identical functions also for the alcohol dehydrogenase classes.