title: MOLECULAR CLONING AND BIOCHEMICAL CHARACTERIZATION OF GALACTOSE-1-PHOSPHATE URIDYLYLTRANSFERASE FROM GRACILARIA CHANGII (RHODOPHYTA)(1).
abstract: 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.
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Rouh-San
authors.initials: RS
authors.lastname: Siow
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Swee-Sen
authors.initials: SS
authors.lastname: Teo
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Wan-Yong
authors.initials: WY
authors.lastname: Ho
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Mohd Yunus Abd
authors.initials: MY
authors.lastname: Shukor
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Siew-Moi
authors.initials: SM
authors.lastname: Phang
authors.affiliation: Faculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, MalaysiaInstitute of Biological Sciences, University of Malaya, 50603 Kuala Lumpur, MalaysiaFaculty of Biotechnology and Biomolecular Sciences, Universiti Putra Malaysia, 43400 UPM-Serdang, Selangor, Malaysia.
authors.forename: Chai-Ling
authors.initials: CL
authors.lastname: Ho
keywords: Gracilaria changii; agar; enzyme activities; galactose-1-phosphate uridylyltransferase; recombinant protein; transcript