Affiliation:
1. Department of Microbiology, University of Georgia, Athens, Georgia 30601
Abstract
Bacteria which utilize mannuronic acid as an energy source were isolated from nature. One of the organisms, identified as a member of the genus
Aeromonas
, used glucuronate, galacturonate, and mannuronate as the sole source of carbon and energy. Glucuronate- and galacturonate-grown resting cells oxidized both glucuronate and galacturonate rapidly, but mannuronate slowly. Mannuronate-grown cells oxidized all three rapidly, with the rate of mannuronate utilization somewhat lower. Cell-free extracts from glucuronate-, galacturonate-, and mannuronate-grown
Aeromonas
C11-2B contained glucuronate and galacturonate isomerases, fructuronate, tagaturonate, and mannuronate reductases, and mannonate and altronate dehydratases, with the exception of glucuronate-grown cells which lacked altronate dehydratase. Thus, the pathway for glucuronate and galacturonate catabolism for
Aeromonas
was identical to
Escherichia coli
. Glucuronate and galacturonate were isomerized to
d
-fructuronate and
d
-tagaturonate which were then reduced by reduced nicotinamide adenine dinucleotide to
d
-mannonate and
d
-altronate, respectively. The hexonic acids were dehydrated to 2-keto-3-deoxy gluconate which was phosphorylated by adenosine triphosphate to 2-keto-3-deoxy-6-phospho gluconate. The latter was then cleaved to pyruvate and glyceraldehyde-3-phosphate. Mannuronate was reduced directly to
d
-mannonate by a reduced nicotinamide adenine dinucleotide phosphate-linked oxidoreductase.
d
-Mannonate was then further broken down as in the glucuronate pathway. The mannuronate reducing enzyme, for which the name
d
-mannonate:nicotinamide adenine dinucleotide (phosphate) oxidoreductase (
d
-mannuronate-forming) was proposed, was shown to be distinct from altronate and mannoate oxidoreductases. This is the first report of a bacterial oxidoreductase which reduces an aldohexuronic acid to a hexonic acid. The enzyme should prove to be a useful analytical tool for determining mannuronate in the presence of other uronic acids.
Publisher
American Society for Microbiology
Subject
Molecular Biology,Microbiology
Reference33 articles.
1. The detection of carbohydrate esters and lactones after separation by paper chromatography;Abdel-Akher M.;J. Am. Chem. Soc.,1951
2. A new pathway of uronic acid metabolism;Ashwell G.;Biochim. Biophys. Acta,1958
3. Uronic acid metabolism in bacteria. I. Purification and properties of uronic acid isomerase in Escherichia colt;Ashwell G.;J. Biol. Chem.,1960
4. Uronic acid metabolism in bacteria. IV. Purification and properties of 2-keto-3-deoxy-D-gluconokinase in Escherichia cott;Cynkin M. A.;J. Biol. Chem.,1960
5. A new specific reaction of hexuronic acids;Dische Z.;J. Biol. Chem.,1947
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