Isolation of Guanosine Diphosphate Uronic Acids from a Marine Brown Alga, Fucus gardneri Silva

From the ¹ From the Department of Biochemistry, University of California, Berkeley, California 94720

Guanosine diphosphate D-mannuronic acid and guanosine diphosphate L-guluronic acid were isolated from the marine brown alga, Fucus gardneri Silva. These uronic acid nucleotides, reported to occur for the first tune in living cells, are considered to be the precursors for the biosynthesis of alginic acid which constitutes about 18% of this alga.

A mixture of 3 µmoles of the two uronic acid nucleotides was isolated from 14 kg of the plant. About 80% of the mixture was identified as GDP-D-mannuronic acid by the following criteria: (a) spectral properties and quantitative chemical analyses of the components, (b) examination of products formed by enzymic and mild acid hydrolysis, (c) chromatographic and electrophoretic mobilities, and (d) characterization of D-mannitol derived from the uronic acid residue by borate electrophoresis, by gas chromatography as the hexaacetate, and by oxidation with D-mannitol dehydrogenase.

The minor uronic acid nucleotide component was characterized as GDP-L-guluronic acid by (a) detection of gulurone and glucitol hexaacetate, respectively, in the preparations of uronolactone and hexitol hexaacetate derived from the nucleotide mixture, and (b) detection of gluconate in the borohydride-reduced uronic acid residue of the nucleotide by the combining action of D-gluconokinase and phosphoglucono-dehydrogenase, or with gluconic dehydrogenase.

Other nucleotides detected in the algal extract include: nicotinamide adenine dinucleotide, cytidine 5'-phosphate, NADP⁺, uridine 5'-phosphate, adenosine 5'-phosphate, a mixture of UDP-D-glucose and UDP-L-arabinose, ADP, GMP, GDP, a mixture of GDP sugars, and an unidentified adenine nucleotide fraction which produced glucose and arabinose upon hydrolysis.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				W. Z. Hassid Biosynthesis of Oligosaccharides and Polysaccharides in Plants Science, July 11, 1969; 165(3889): 137 - 144. [PDF]