@article {972,
	title = {Active site mutants of the "non-hydrolyzing" UDP-N-acetylglucosamine 2-epimerase from Escherichia coli},
	journal = {Biochimica Et Biophysica Acta-Proteins and Proteomics},
	volume = {1700},
	number = {1},
	year = {2004},
	note = {ISI Document Delivery No.: 833VCTimes Cited: 4Cited Reference Count: 26},
	month = {Jul},
	pages = {85-91},
	type = {Article},
	abstract = {The "non-hydrolyzing" bacterial UDP-N-acetylglucosamine 2-epimerase catalyzes the reversible interconversion of UDP-N-acetylglucosarnine (UDP-GlcNAc) and UDP-N-acetylmannosamine (UDP-ManNAc). This homodimeric enzyme is allosterically activated by its substrate, UDP-GlcNAc, and it is thought that one subunit plays a regulatory role, while that of the other plays a catalytic role. In this work, five active site mutants were prepared (D95N, E117Q, E131Q, K15A, and H213N) and analyzed in terms of their effects on binding, catalysis, and allosteric regulation. His213 appears to play a role in UDP binding and may also assist in catalysis and/or regulation, but is not a key catalytic residue. Lys15 appears to be quite important for binding. All three of the carboxylate mutants showed dramatic decreases in the value of k(cat) but relatively unaffected values of Km. Thus, these residues are playing key roles in catalysis and/or regulation. In the case of E117Q, the reaction intermediates are released into solution at a rate comparable to that of the overall catalysis. This may indicate that Glu117 plays the role as an acid/base catalyst in the second step of the UDP-GlcNAc epimerization reaction. All three carboxylate mutants were found to exhibit impaired allosteric control. (C) 2004 Elsevier B.V. All rights reserved.},
	keywords = {2-acetamidoglucal, 2-EPIMERASE/N-ACETYLMANNOSAMINE KINASE, ACID BIOSYNTHESIS, allosteric regulation, enterobacterial common antigen, EPIMERIZATION, HOMOLOGY, MECHANISM, MUTAGENESIS, RAT-LIVER, SEQUENCE, sialic acid, STREPTOCOCCUS-PNEUMONIAE, TRANSFERASES, UDP-N-acetylmannosamine},
	isbn = {1570-9639},
	url = {<Go to ISI>://000222367400011},
	author = {Samuel, J. and Tanner, M. E.}
}
@article {494,
	title = {Mechanistic aspects of enzymatic carbohydrate epimerization},
	journal = {Natural Product Reports},
	volume = {19},
	number = {3},
	year = {2002},
	note = {ISI Document Delivery No.: 566QLTimes Cited: 21Cited Reference Count: 214},
	month = {Jun},
	pages = {261-277},
	type = {Review},
	abstract = {Carbohydrate epimerases are enzymes that catalyze an inversion of stereochemistry at a stereogenic center in a sugar. This review focuses on the mechanistic strategies that are employed by this diverse family of enzymes, and is divided into the following sections: deprotonation/reprotonation, transient oxidation, cofactor independent, and mutarotation. The review is comprehensive up to Oct. 2001 and contains 216 references.},
	keywords = {2-EPIMERASE, ACETYLNEURAMINIC, ACID BIOSYNTHESIS, D-GLUCOSAMINE 2-EPIMERASE, D-MANNOHEPTOSE 6-EPIMERASE, GDP-L-FUCOSE, GLUCURONYL C-5 EPIMERASE, MANNURONAN C-5-EPIMERASE, N-ACETYLGLUCOSAMINE, RENIN-BINDING PROTEIN, SITE-DIRECTED MUTAGENESIS, UDP-GALACTOSE 4-EPIMERASE, VINELANDII},
	isbn = {0265-0568},
	url = {<Go to ISI>://000176439700001},
	author = {Samuel, J. and Tanner, M. E.}
}
