title: The glucose effect and regulation of alpha-amylase synthesis in the hyperthermophilic archaeon Sulfolobus solfataricus.
abstract: An alpha-amylase was purified from culture supernatants of Sulfolobus solfataricus 98/2 during growth on starch as the sole carbon and energy source. The enzyme is a homodimer with a subunit mass of 120 kDa. It catalyzes the hydrolysis of starch, dextrin, and alpha-cyclodextrin with similar efficiencies. Addition of exogenous glucose represses production of alpha-amylase, demonstrating that a classical glucose effect is operative in this organism. Synthesis of [35S]-alpha-amylase protein is also subject to the glucose effect. alpha-Amylase is constitutively produced at low levels but can be induced further by starch addition. The absolute levels of alpha-amylase detected in culture supernatants varied greatly with the type of sole carbon source used to support growth. Aspartate was identified as the most repressing sole carbon source for alpha-amylase production, while glutamate was the most derepressing. The pattern of regulation of alpha-amylase production seen in this organism indicates that a catabolite repression-like system is present in a member of the archaea.
authors.affiliation: School of Biological Sciences, University of Nebraska, Lincoln 68588-0666, USA.
authors.forename: C
authors.initials: C
authors.lastname: Haseltine
authors.forename: M
authors.initials: M
authors.lastname: Rolfsmeier
authors.forename: P
authors.initials: P
authors.lastname: Blum
mesh_terms: D004790:Enzyme Induction; D004794:Enzyme Repression; D015964:Gene Expression Regulation, Bacterial; D005947:Glucose / Q000494:pharmacology*; D008969:Molecular Sequence Data; D013213:Starch / Q000378:metabolism*; D016944:Sulfolobus / Q000187:drug effects / Q000201:enzymology*; D000516:alpha-Amylases / Q000096:biosynthesis* / Q000302:isolation & purification
chemical_list: D013213:Starch; D000516:alpha-Amylases; D005947:Glucose