In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 98, No. 26 ( 2001-12-18), p. 14843-14848
Abstract:
The first step in the biosynthetic pathway of vitamin C in
plants is the formation, at the level of sugar nucleotide, of l -galactosyl residues, catalyzed by a largely unknown
GDP- d -mannose 3",5"-epimerase. By using combined
conventional biochemical and mass spectrometry methods, we obtained a highly purified preparation of GDP- d -mannose
3",5"-epimerase from an Arabidopsis thaliana cell
suspension. The native enzyme is an 84-kDa dimer, composed of two apparently identical subunits. In-gel tryptic digestion of the enzyme
subunit, followed by peptide sequencing and a blast search,
led to the identification of the epimerase gene. The closest homolog of the plant epimerase is the BlmG gene product of Streptomyces sp., a putative NDP- d -mannose
5"-epimerase. The plant GDP- d -mannose 3",5"-epimerase is,
to our knowledge, a novel member of the extended short-chain dehydrogenase/reductase family. The enzyme was cloned and expressed
in Escherichia coli cells.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.011578198
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2001
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
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