ISSN:
1574-6968
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Abstract Suspensions of maltose-grown cells of the hyperthermophilic archaeon Pyrococcus furiosus, when incubated at 90°C with 35 mM [1-13C]glucose or [3-13C]glucose, consumed glucose at a rate of about 10 nmol min−1 (mg protein)−1. Acetate (10 mM), alanine (3 mM), CO2 and H2 were the fermentation products. The 13C-labelling pattern in alamine and acetate were analyzed. With [1-13C]glucose the methyl group of both alanine and acetate was labelled; with [3-13C]glucose only the carboxyl group of alanine was labelled whereas acetate was unlabelled. Extracts of maltose-grown cells contained glucose isomerase (12.8 U mg−1, 100°C), ketohexokinase (0.23 U mg−1, 100°C), and fructose 1-phosphate aldolase (0.06 U mg−1, 100°C). Enzymes catalyzing the formation of fructose 1,6-bisphosphate from fructose 1-phosphate or fructose 6-phosphate could not be detected. As publihed previously by our group and other authors P. furiosus also contains enzymes of glyceraldehyde conversion to 2-phosphoglycerate according to a non-phosphorylated Entner-Doudoroff pathway, of dihydroxyacetone phosphate conversion to 2-phosphoglycerate according to the Embden-Meyerhof pathway, and of 2-phosphoglycerate conversion - via pyruvate - to acetate and alanine. Based on the enzyme activities in P. furiosus, the following pathway for glucose degradation to alanine and acetate in cell suspensions is proposed which can explain the [13C]glucose labelling data: glucose→fructose→fructose 1-phosphate→dihydroxyacetonephosphate+glyceraldehyde and further conversion of both trioses to alanine and acetate via pyruvate.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1574-6968.1994.tb07083.x
Permalink
