@article {2279,
	title = {Transient oxidation as a mechanistic strategy in enzymatic catalysis},
	journal = {Current Opinion in Chemical Biology},
	volume = {12},
	number = {5},
	year = {2008},
	note = {ISI Document Delivery No.: 375SZTimes Cited: 1Cited Reference Count: 41Tanner, Martin E.},
	month = {Oct},
	pages = {532-538},
	type = {Review},
	abstract = {Enzymes that employ a transient oxidation mechanism catalyze transformations that are overall redox neutral, but involve intermediates that have a higher oxidation state than the substrates or products. An oxidation/reduction sequence may be used directly to promote isomerization reactions or indirectly to permit the formation of stabilized intermediates such as carbanions. This review will focus on three recent examples of nicotinamide-dependent enzymes that have been found to employ transient oxidation during catalysis: ADP-L-glycero-D-manno-heptose 6-epimerase, GDP-mannose 3,5-epimerase, and the 6-phosphoglucosidases from family 4. These enzymes are remarkable in their ability to catalyze either nonstereospecific hydride transfers or multiple chemical steps within a single active site.},
	keywords = {ACTIVE-SITE, ALPHA-GLUCOSIDASE, BACILLUS-SUBTILIS, CRYSTAL-STRUCTURE, D-MANNO-HEPTOSE, D-MANNOHEPTOSE 6-EPIMERASE, DEHYDROQUINATE SYNTHASE, ESCHERICHIA-COLI, THERMOTOGA-MARITIMA, UDP-GALACTOSE 4-EPIMERASE},
	isbn = {1367-5931},
	url = {<Go to ISI>://000261134900010},
	author = {Tanner, M. E.}
}
@article {1213,
	title = {Dismutase activity of ADP-L-glycero-D-manno-heptose 6-epimerase: Evidence for a direct oxidation/reduction mechanism},
	journal = {Biochemistry},
	volume = {44},
	number = {15},
	year = {2005},
	note = {ISI Document Delivery No.: 916ZNTimes Cited: 11Cited Reference Count: 33},
	month = {Apr},
	pages = {5907-5915},
	type = {Article},
	abstract = {The first positive evidence for the utilization of a direct C-6" oxidation/reduction mechanism by ADP-L-glycero-D-manno-heptose 6-epimerase is reported here. The epimerase (HldD or AGME, formerly RfaD) operates in the biosynthetic pathway Of L-glycero-D-manno-heptose, which is a conserved sugar in the core region of lipopolysaccharide (LPS) of Gram-negative bacteria. The stereochemical inversion catalyzed by the epimerase is interesting as it occurs at an "unactivated" stereocenter that lacks an acidic C-H bond, and therefore, a direct deprotonation/reprotonation mechanism cannot be employed. Instead, the epimerase employs a transient oxidation strategy involving a tightly bound NADP(+) cofactor. A recent study ruled out mechanisms involving transient oxidation at C-4 {\textquoteright}{\textquoteright} and C-7 {\textquoteright}{\textquoteright} and supported a mechanism that involves an initial oxidation directly at the C-6 {\textquoteright}{\textquoteright} position to generate a 6"-keto intermediate (Read, J. A., Ahmed, R. A., Morrison, J. P., Coleman, W. G., Jr., Tanner, M. E. (2004) J. Am. Chem. Soc. 126, 8878-8879). A subsequent nonstereospecific reduction of the ketone intermediate can generate either epimer of the ADP-heptose. In this work, an intermediate analogue containing an aldehyde functionality at C-6 {\textquoteright}{\textquoteright}, ADP-beta-D-manno-hexodialdose, is prepared in order to probe the ability of the enzyme to catalyze redox chemistry at this position. It is found that incubation of the aldehyde with a catalytic amount of the epimerase leads to a dismutation process in which one-half of the material is oxidized to ADP-beta-D-mannuronic acid and the other half is reduced to ADP-beta-D-mannose. Transient reduction of the enzyme-bound NADP(+) was monitored by UV spectroscopy and implicates the cofactor{\textquoteright}s involvement during catalysis.},
	keywords = {ACID, ALCOHOL-DEHYDROGENASE, ALDEHYDE DEHYDROGENASE, D-MANNOHEPTOSE 6-EPIMERASE, DROSOPHILA-MELANOGASTER, EPIMERIZATION, ESCHERICHIA-COLI, GLUCOSE DEHYDROGENASE, LIVER, SITE RESIDUES, UDP-GALACTOSE 4-EPIMERASE},
	isbn = {0006-2960},
	url = {<Go to ISI>://000228425600037},
	author = {Morrison, J. P. and Read, J. A. and Coleman, W. G. and Tanner, M. E.}
}
@article {1234,
	title = {Efficient chemoenzymatic synthesis of ADP-D-glycero-beta-D-manno-heptose and a mechanistic study of ADP-L-glycero-D-manno-heptose 6-epimerase},
	journal = {Organic Letters},
	volume = {7},
	number = {12},
	year = {2005},
	note = {ISI Document Delivery No.: 932SSTimes Cited: 10Cited Reference Count: 21},
	month = {Jun},
	pages = {2457-2460},
	type = {Article},
	abstract = {[GRAPHICS] A chemoenzymatic synthesis of ADP-D-glycero-\&beta;-D-manno-heptose (ADP-D,D-Hep) is described in which D,D-Hep 7-phosphate is converted to ADP-D,D-Hep by two biosynthetic enzymes. This strategy allows access to the 6"-deuterated analogue, which upon incubation with the epimerase showed complete retention of the isotopic label at the 6"-position. This provides evidence for a direct oxidation mechanism in which the hydride initially transferred to the NADP(+) cofactor is subsequently returned to the same carbon in a nonstereospecific manner.},
	keywords = {biosynthesis, CARBON, D-MANNOHEPTOSE 6-EPIMERASE, EPIMERIZATION, PATHWAY},
	isbn = {1523-7060},
	url = {<Go to ISI>://000229574300042},
	author = {Read, J. A. and Ahmed, R. A. and Tanner, M. E.}
}
@article {966,
	title = {The mechanism of the reaction catalyzed by ADP-beta-L-glycero-D-manno-heptose 6-epimerase},
	journal = {Journal of the American Chemical Society},
	volume = {126},
	number = {29},
	year = {2004},
	note = {ISI Document Delivery No.: 840JTTimes Cited: 14Cited Reference Count: 24},
	month = {Jul},
	pages = {8878-8879},
	type = {Article},
	keywords = {4, 6-DEHYDRATASE, BACTERIA, D-MANNOHEPTOSE 6-EPIMERASE, EPIMERIZATION, ESCHERICHIA-COLI, GLUCOSE, INSIGHTS, NUCLEOTIDE-MODIFYING ENZYMES, OUTER-MEMBRANE, UDP-GALACTOSE 4-EPIMERASE},
	isbn = {0002-7863},
	url = {<Go to ISI>://000222855300009},
	author = {Read, J. A. and Ahmed, R. A. and Morrison, J. P. and Coleman, W. G. 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.}
}
