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MOLECULAR CLONING AND BIOCHEMICAL CHARACTERIZATION OF GALACTOSE-1-PHOSPHATE URIDYLYLTRANSFERASE FROM GRACILARIA CHANGII (RHODOPHYTA)1
Article first published online: 20 DEC 2011
© 2011 Phycological Society of America
Journal of Phycology
Volume 48, Issue 1, pages 155–162, February 2012
How to Cite
Siow, R.-S., Teo, S.-S., Ho, W.-Y., Shukor, Mohd. Y. Abd., Phang, S.-M. and Ho, C.-L. (2012), MOLECULAR CLONING AND BIOCHEMICAL CHARACTERIZATION OF GALACTOSE-1-PHOSPHATE URIDYLYLTRANSFERASE FROM GRACILARIA CHANGII (RHODOPHYTA). Journal of Phycology, 48: 155–162. doi: 10.1111/j.1529-8817.2011.01105.x
Received 15 September 2010. Accepted 30 June 2011.
- Issue published online: 1 FEB 2012
- Article first published online: 20 DEC 2011
- enzyme activities;
- galactose-1-phosphate uridylyltransferase;
- Gracilaria changii;
- recombinant protein;
Galactose-1-phosphate uridylyltransferase (GALT) catalyzes the reversible conversion of glucose-1-phosphate and UDP-galactose to galactose-1-phosphate and UDP-glucose. This enzyme is also responsible for one of the biochemical steps that produce the precursors of agar and agarose. In this study, we report the molecular cloning and sequence analyses of a cDNA encoding GALT, from Gracilaria changii (B. M. Xia et I. A. Abbott) I. A. Abbott, J. Zhang et B. M. Xia, which constitutes a genus of seaweeds that supply more than 60% of the world’s agar and agarose. We have subcloned this cDNA into a bacterial expression cloning vector and characterized the enzyme activities of its recombinant proteins in vitro. The GcGALT gene was shown to be up-regulated by salinity stresses. The abundance of transcripts encoding GcGALT was the highest in G. changii, followed by Gracilaria edulis and Gracilaria salicornia in a descending order, corresponding to their respective agar contents. Our findings indicated that GALT could be one of the components that determines the agar yield in Gracilaria species.