Utilization of gluconate by Escherichia coli. A role of adenosine 3′:5′-cyclic monophosphate in the induction of gluconate catabolism

Abstract

1. Cultures of Escherichia coli growing on gluconate use both gluconate and glucose when glucose is added. 2. Glycerol-grown cells adapt to gluconate utilization even in media containing glucose as well as gluconate. 3. The rates of gluconate utilization by cells growing on a mixture ofglucose and gluconate, and the specific activities ofthe gluconate uptake system and of gluconate kinase, are greater if adenosine 3': 5'-cyclic monophosphate (cyclic AMP) is present in the medium than in its absence. 4. Growth on media containing gluconate and cyclic AMP is accompanied by the formation of methyl glyoxal and pyruvate, and progressive inhibition of growth. 5. A mutant devoid of adenylate cyclase activity (cya) grew well on glucose in the absence of exogenous cyclic AMP but grew only poorly on gluconate; neither the gluconate uptake system nor gluconate kinase was adequately induced. The addition of cyclic AMP promoted growth on gluconate and facilitated the induction of proteins required for gluconate catabolism. 6. Phage P1-mediated transduction of cya+ into the cya-mutant also restored the wild-type phenotype in its ability to adapt to gluconate utilization.When cultures of Escherichia coli are placed in growth media containing both glucose and any one of a wide range of carbohydrates, glucose is used preferentially and the proteins required for the uptake and catabolism of the other carbohydrate are inducibly formed only after the glucose has been virtually used up. This phenomenon, originally termed the 'glucose effect' (Monod, 1942), is made up of at least two components (Lengeler, 1966 Monod, 1968;Pastan & Perlman, 1970, 1971

Cloning and molecular genetic characterization of the Escherichia coli gntR, gntK, and gntU genes of GntI, the main system for gluconate metabolism

“…The modest catabolite repression of gntKU transcription (4-fold), by virtue of a CAP-binding site at the gntK promoter, confirms measurements of gluconokinase and gluconate transport made by others (2). It is quite interesting that gntK and gntU are subject to glucose catabolite repression, considering that gluconate is deemed to be more catabolite repressing than glucose (30).…”

“…It has long been thought that the high-affinity gluconate transporter encoded by gntT plays a primary role in gluconate metabolism, as does gntK, which encodes the primary gluconokinase (2,33). Previous reports indicate that the high-affinity (GntT) gluconate transporter is induced for growth on gluconate while the lowaffinity transporter (GntU) is not (14,33,34).…”

“…It is quite interesting that gntK and gntU are subject to glucose catabolite repression, considering that gluconate is deemed to be more catabolite repressing than glucose (30). Nevertheless, the 4-fold-lower level of gntKU expression is still sufficient for cometabolism of glucose and gluconate (2,13). It is probably important that the edd and eda genes of the Entner-Doudoroff pathway are not catabolite repressed by glucose (11).…”

The Entner-Doudoroff pathway: history, physiology and molecular biology

“…The alternative branches consist of: (1) PTSmediated glucose transport, or (2) glucose oxidation to gluconate and subsequent transport, phosphorylation and catabolism via the gluconate-inducible Entner-Doudoroff pathway. This pathway would of course be functional only in the absence of catabolite repression of the Entner-Doudoroff enzymes, which has been reported [44]. Eisenberg and Dobrogosz [34] showed that gluconate and glucose can be degraded simultaneously by E.…”

The metabolism of gluconate in Escherichia coli: A study in continuous culture

“…E. coli gntT mutants are severely affected in the utilization of gluconate; moreover, some E. coli bioH-asd deleted mutants are unable to grown on this substrate (NAGEL DE ZWAIG et al 1973, FAIK and KORNBERG 1973ISTURIZ et al 1979. These and other observations suggested the GntI and GntII systems involved as main and subsidiary respectively, in the capture and phosphorylation ofgluconate (BACHI and KORNBERG 1975 a).The GntI and GntII activities convert external gluconate to intracellular 6-phosphogluconate, which can either be decarboxylated to pentose-phosphate by the action of the enzyme 6-phosphogluconate dehydrogenase (EC 1.1.1.44., gene gnd) or metabolized to pyruvate and glyceraldehyde 3-phosphate via the ENTNER-DOUDOROFF pathway (EISEN-BERG and DOBROGOSZ 1967). The first enzyme involved in the latter pathway, 6-phosphogluconate dehydratase (EC 4.2.1.12., gene edd), as well as the GntI and GntII activities are induced when the cells are cultivated in gluconate-containing media (COHEN 1951, FRAENKEL and LEVISOHN 1967, NAGEL DE ZWAIG et a/., 1973, POUYSS~GUR et a/.…”