UGE (UDP-Glc 4-epimerase or UDP-Gal 4-epimerase; EC 5.1.3.2) catalyses the interconversion of UDP-Gal and UDP-Glc. Both nucleotide sugars act as activated sugar donors for the biosynthesis of cell wall polysaccharides such as cellulose, xyloglucans, (1,3;1,4)-β-D-glucan and pectins, together with other biologically significant compounds including glycoproteins and glycolipids. Three members of the HvUGE (barley UGE) gene family, designated HvUGE1, HvUGE2 and HvUGE3, have been characterized. Q-PCR (quantitative real-time PCR) showed that HvUGE1 mRNA was most abundant in leaf tips and mature roots, but its expression levels were relatively low in basal leaves and root tips. The HvUGE2 gene was transcribed at significant levels in all organs examined, while HvUGE3 mRNA levels were very low in all the organs. Heterologous expression of a near full-length cDNA confirmed that HvUGE1 encodes a functional UGE. A non-covalently bound NAD+ was released from the enzyme after denaturing with aqueous ethanol and was identified by its spectrophotometric properties and by electrospray ionization MS. The Km values were 40 μM for UDP-Gal and 55 μM for UDP-Glc. HvUGE also catalyses the interconversion of UDP-GalNAc and UDP-GlcNAc, although it is not known if this has any biological significance. A three-dimensional model of the HvUGE revealed that its overall structural fold is highly conserved compared with the human UGE and provides a structural rationale for its ability to bind UDP-GlcNAc.
Skip Nav Destination
Article navigation
February 2006
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkEditorial Board
Research Article|
January 27 2006
Gene expression patterns and catalytic properties of UDP-D-glucose 4-epimerases from barley (Hordeum vulgare L.)
Qisen Zhang;
Qisen Zhang
1Australian Centre for Plant Functional Genomics, School of Agriculture and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
Search for other works by this author on:
Maria Hrmova;
Maria Hrmova
1Australian Centre for Plant Functional Genomics, School of Agriculture and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
Search for other works by this author on:
Neil J. Shirley;
Neil J. Shirley
1Australian Centre for Plant Functional Genomics, School of Agriculture and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
Search for other works by this author on:
Jelle Lahnstein;
Jelle Lahnstein
1Australian Centre for Plant Functional Genomics, School of Agriculture and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
Search for other works by this author on:
Geoffrey B. Fincher
Geoffrey B. Fincher
1
1Australian Centre for Plant Functional Genomics, School of Agriculture and Wine, University of Adelaide, Waite Campus, Glen Osmond, SA 5064, Australia
1To whom correspondence should be addressed (email geoff.fincher@adelaide.edu.au).
Search for other works by this author on:
Publisher: Portland Press Ltd
Received:
August 15 2005
Revision Received:
November 01 2005
Accepted:
November 03 2005
Accepted Manuscript online:
November 03 2005
Online ISSN: 1470-8728
Print ISSN: 0264-6021
The Biochemical Society, London
2006
Biochem J (2006) 394 (1): 115–124.
Article history
Received:
August 15 2005
Revision Received:
November 01 2005
Accepted:
November 03 2005
Accepted Manuscript online:
November 03 2005
Citation
Qisen Zhang, Maria Hrmova, Neil J. Shirley, Jelle Lahnstein, Geoffrey B. Fincher; Gene expression patterns and catalytic properties of UDP-D-glucose 4-epimerases from barley (Hordeum vulgare L.). Biochem J 15 February 2006; 394 (1): 115–124. doi: https://doi.org/10.1042/BJ20051329
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Captcha Validation Error. Please try again.