Industrial Biotransformations

GlcNAc 2-epimerase
Escherichia coli
1 = N-acetyl-D-glucosamine
2 = N-acetyl-D-mannosamine
Fig. 5.1.3.8 – 1
1) Reaction conditions
[1]: 0.8 M, 177 g · L –1 [221.21 g · mol –1 ]
pH: 7.2
T: 30 °C
medium: aqueous
reaction type: epimerization
catalyst: solubilized enzyme
enzyme: N-acyl-d-glucosamine 2-epimerase (N-acylglucosamine 2-epimerase)
strain: Escherichia coli
CAS (enzyme): [37318–34–6]
2) Remarks
● This biotransformation is integrated into the production of N-acetylneuraminic acid (Neu5Ac),
see page 340.
● By application of the N-acylglucosamine 2-epimerase it is possible to start with the inexpensive
N-acetyl-d-glucosamine instead of N-acetyl-d-mannosamine.
● The epimerase is used for the in situ synthesis of N-acetyl-d-mannosamine (ManNAc). Since
the equilibrium is on the side of the educt, the reaction is driven by the subsequent transformation
of ManNAc and pyruvate to Neu5Ac.
● The N-acylglucosamine 2-epimerase is cloned from porcine kidney and transformed and overexpressed
in Escherichia coli.
● To reach maximal axctivitiy ATP and Mg 2+ need to be added.
● Since the whole synthesis is reversible high GlcNAc concentrations are used.
● The chemical epimerization of GlcNAc is employed by Glaxo (page 459).
3) Flow scheme
Not published.
506
HO HO
HO
O
OH
NHAc
E
HO HO
HO
1 2
NHAc
O
OH
EC 5.1.3.8
Marukin Shoyu Co., Ltd.