title: Alkaline biocatalysis for the direct synthesis of N-acetyl-D-neuraminic acid (Neu5Ac) from N-acetyl-D-glucosamine (GlcNAc).
abstract: Integration between the alkaline epimerization of N-acetyl-D-glucosamine (GlcNAc) to N-Acetyl-D-mannosamine (ManNAc) and the N-acetyl-D-neuraminic acid (Neu5Ac) aldolase-catalyzed biotransformation has been assessed experimentally. GlcNAc epimerization took place above pH 9.0, and the initial rate of ManNAc formation increased exponentially to 10.37 mmol/L per hour at pH 12. However, above this pH, severe degradation of pyruvate occurred. A value of 31.3% molar conversion on Pyr was achieved in an integrated biotransformation. The "pseudo"-steady state at the end of the reaction was comparable to the equilibrium achieved with a combination of an epimerase and aldolase enzymes. The integrated reaction proved feasible, but at the expense of pyruvate and Neu5Ac aldolase degradation.
authors.affiliation: The Advanced Centre for Biochemical Engineering, Department of Biochemical Engineering, University College London, London WC1E 7JE, United Kingdom.
authors.forename: S
authors.initials: S
authors.lastname: Blayer
authors.forename: J M
authors.initials: JM
authors.lastname: Woodley
authors.forename: M J
authors.initials: MJ
authors.lastname: Dawson
authors.forename: M D
authors.initials: MD
authors.lastname: Lilly
mesh_terms: D000117:Acetylglucosamine / Q000737:chemistry*; D001711:Biotransformation; D002384:Catalysis; D002851:Chromatography, High Pressure Liquid; D005240:Feasibility Studies; D005634:Fructose-Bisphosphate Aldolase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D019158:N-Acetylneuraminic Acid / Q000138:chemical synthesis* / Q000737:chemistry; D011773:Pyruvates / Q000737:chemistry
chemical_list: D011773:Pyruvates; D005634:Fructose-Bisphosphate Aldolase; D019158:N-Acetylneuraminic Acid; D000117:Acetylglucosamine