UDPgalactose 4-epimerase from Saccharomyces cerevisiae A bifunctional enzyme with aldose 1-epimerase activity
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
UDPgalactose 4-epimerase from Saccharomyces cerevisiae
A bifunctional enzyme with aldose 1-epimerase activity
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| Creator |
Majumdar, Siddhartha
Ghatak, Jhuma Mukherji, Sucheta Bhattacharjee, Hiranmoy Bhaduri, Amar |
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| Subject |
Cell Biology & Physiology
Drug Development/Diagnostics & Biotechnology |
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| Description |
UDPgalactose 4-epimerase (epimerase) catalyzes the
reversible conversion between UDPgalactose and UDPglucose
and is an important enzyme ofthe galactose metabolic
pathway. The Saccharomyces cerevisiae epimerase encoded
by the GAL10 gene is about twice the size ofeither the
bacterial or human protein. Sequence analysis indicates that
the yeast epimerase has an N-terminal domain (residues
1–377) that shows significant similarity with Escherichia coli
and human UDPgalactose 4-epimerase, and a C-terminal
domain (residues 378–699), which shows extensive identity
to either the bacterial or human aldose 1-epimerase (mutarotase).
The S. cerevisiae epimerase was purified to >95%
homogeneity by sequential chromatography on DEAESephacel
and Resource-Q columns. Purified epimerase
preparations showed mutarotase activity and could convert
either a-D-glucose or a-D-galactose to their b-anomers.Induction ofcells with galactose led to simultaneous
enhancement ofboth epimerase and mutarotase activities.
Size exclusion chromatography experiments confirmed that
the mutarotase activity is an intrinsic property ofthe yeast
epimerase and not due to a copurifying endogenous mutarotase.
When the purified protein was treated with 5¢-UMP
and L-arabinose, epimerase activity was completely lost but
the mutarotase activity remained unaffected. These results
demonstrate that the S. cerevisiae UDPgalactose 4-epimerase
is a bifunctional enzyme with aldose 1-epimerase
activity.The active sites for these two enzymatic activities are
located in different regions ofthe epimerase holoenzyme.
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| Publisher |
Blackwell Publishing
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| Date |
2004
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/747/1/EUROPEAN_JOURNAL_OF_BIOCHEMISTRY%2C__271(_4)%2C_753%2D759[83].pdf
Majumdar, Siddhartha and Ghatak, Jhuma and Mukherji, Sucheta and Bhattacharjee, Hiranmoy and Bhaduri, Amar (2004) UDPgalactose 4-epimerase from Saccharomyces cerevisiae A bifunctional enzyme with aldose 1-epimerase activity. European Journal Of Biochemistry, 271 (4). pp. 753-759. |
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| Relation |
http://dx.doi.org/10.1111/j.1432-1033.2003.03974.x
http://www.eprints.iicb.res.in/747/ |
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