Received 15 January 1991. Accepted 22 July 1991.
FORMATION OF NUCLEOSIDE DIPHOSPHATE MONOSACCHARIDES (NDP-SUGARS) BY THE AGAROPHYTE PTEROCLADIA CAPILLACEA (RHODOPHYCEAE)1
Article first published online: 27 OCT 2004
Journal of Phycology
Volume 27, Issue 6, pages 702–709, December 1991
How to Cite
Manley, S. L. and Burns, D. J. (1991), FORMATION OF NUCLEOSIDE DIPHOSPHATE MONOSACCHARIDES (NDP-SUGARS) BY THE AGAROPHYTE PTEROCLADIA CAPILLACEA (RHODOPHYCEAE). Journal of Phycology, 27: 702–709. doi: 10.1111/j.0022-3646.1991.00702.x
This study was supported by an SB1R grant from NSF (1986) to Ocean Genetics, Inc., Santa Cruz, California.
- Issue published online: 27 OCT 2004
- Article first published online: 27 OCT 2004
- agar biosynthesis;
- nudeoside diphosphate monosaccharides;
- Pterocladia capillacea;
The following nucleoside diphosphate monosaccharides (sugar nucleotides) were identified by HPLC from Pterocladia capillacea Born and Thur.: ADP-glucose, UDP-glucose, UDP-d-galactose, and GDP-glucose + mannose. GDP-l-galactose was not identified due to the lack of a standard. Several extraction methods were evaluated for their efficacy. A freeze/ thaw (liquid N2) step fallowed by formic acid (1 M) extraction, reduced pressure evaporation, and solubilization in water was the preferred method. Differences in media nitrate that resulted in different tissue-N levels (1.8, 2.3, and 3.5% dry wt) and agar yields (34, 31, and 28% dry wt, respectively) also resulted in a marked difference in UDP-d-galactose and ADP-glucose tissue levels (decrease with increasing tissue-N) while the levels of the other sugar nucleotide agar precursors remained unchanged. Activities of UDP-glucose, GDP-glucose, and GDP-mannose pyrophosphorylases, and UDP-D-glucose-4-epimerase were detected in cell-free extracts using unlabeled and 14C-labeled substrates. This study-strongly supports the proposition that the d-galactose component of agar is synthesized via G-1-P UDP-glucose UDP-d-galactose and that, the l-galactoae component is produced via mannose-1-P GDP-mannose GDP-l-galactose.