Galactose- und Glucose-Stoffwechsel in Haloferax volcaniiAbbauwege, Enzyme und transkriptionelle Regulation

Genome analyses suggest that in the halophilic archaeon Haloferax volcanii galactose is degraded via a DeLey-Doudoroff pathway (DD). The transport of galactose and the enzymes involved in galactose degradation in H. volcanii have not been characterized so far. Genome analyses of the halophilic archaeon Halorhabdus utahensis suggest, that galactose, in contrast to H. volcanii, is degraded via the classical Leloir-pathway. Enzymes involved in galactose degradation in H. utahensis have not been analyzed so far. Furthermore, recent studies indicate that glucose is degraded via a semiphosphorylative Entner-Doudoroff pathway (spED). The key enzyme of this pathway, KDPG aldolase, has not been characterized in detail. Also, the enzymes involved in oxidation of glyceraldehyde-3-phosphate (GAP), an intermediate of galactose and glucose catabolism in H. volcanii, have not been analyzed so far. In this thesis the transport and degradation of galactose as well as transcriptional regulation of the genes involved in galactose degradation in H. volcanii were investigated. In H. utahensis the key enzyme of Leloir pathway was characterized. Moreover, KDPG aldolase, the key enzyme of glucose degradation as well as enzymes catalyzing GAP oxidation to 3-phosphoglycerate were investigated in detail in H. volcanii. The following results were obtained in this thesis...