Research Library

open-access-imgOpen AccessHeterotrophic Metabolism of the Chemolithotroph Thiobacillus ferrooxidans
Robert Tabita,
D. G. Lundgren
Publication year1971
Publication title
journal of bacteriology
Resource typeJournals
PublisherAmerican Society for Microbiology
Glucose-6-phosphate dehydrogenase and the enzymes of the Entner-Doudoroff pathway, 6-phosphogluconate dehydrase and 2-keto-3-deoxy-6-phosphogluconate aldolase (assayed together), are induced during heterotrophic growth ofThiobacillus ferrooxidans on an iron-glucose-supplemented medium or on glucose alone. By contrast, autotrophic cells (iron-grown) contain low levels of these enzymes. Fructose 1, 6-diphosphate aldolase, an enzyme of the Embden-Meyerhof pathway, is present at low levels irrespective of the growth medium, suggesting that this enzyme is not involved in energy-yielding reactions but merely provides intermediates for biosynthesis. The Entner-Doudoroff and pentose-phosphate pathways are the principle means through which glucose is dissimilated and is presumed to be concerned with energy production. Isotopic studies showed that a high rate of CO2 formation from specifically labeled glucose came from carbon atoms 1 and 4. An unexpectedly high rate of evolution of CO2 also came from carbon 6, suggesting that the triose phosphate formed during glucose breakdown and specifically as a result of 2-keto-3-deoxy-6-phosphogluconate aldolase activity, was metabolized via some unorthodox metabolic route. Cells grown in the iron-supplemented and glucose-salts media have a complete tricarboxylic acid cycle, whereas autotrophically grownT. ferrooxidans lacked both α-ketoglutarate dehydrogenase and reduced nicotinamide adenine dinucleotide oxidase. Two isocitrate dehydrogenases [nicotinamide adenine dinucleotide (NAD) and NAD phosphate (NADP) specific] were present. NAD-linked enzyme was constitutive, whereas the NADP-linked enzyme was induced upon adaptation of autotrophic cells to heterotrophic growth.
Subject(s)aldolase a , bacteria , biochemistry , biology , citric acid cycle , dehydrogenase , dihydroxyacetone phosphate , ecology , energy source , enzyme , fructose bisphosphate aldolase , genetics , glycolysis , heterotroph , isocitrate dehydrogenase , metabolism , nad+ kinase , nicotinamide adenine dinucleotide , nicotinamide adenine dinucleotide phosphate , oxidase test , pentose phosphate pathway , renewable energy , thiobacillus
SCImago Journal Rank1.652

Seeing content that should not be on Zendy? Contact us.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.
Having issues? You can contact us here