Izvorni znanstveni članak
Modelling Enzymatic Reduction of 2-keto-D-glucose by Suspended Aldose Reductase
G. Maria
orcid.org/0000-0003-3650-676X
; University Politehnica of Bucharest, Department of Chemical & Biochemical Engineering, Polizu Str. 1, 011061 Bucharest, P.O. 35-107, Romania
M. D. Ene
; University Politehnica of Bucharest, Department of Chemical & Biochemical Engineering, Polizu Str. 1, 011061 Bucharest, P.O. 35-107, Romania; Biotehnos Co. s.a., R&D Department, Gorunului Str. 3-5, 075100 Otopeni, Romania
Sažetak
Batch experiments have been systematically carried out at 25 °C, pH = 7, over 24- 76 h reaction time in order to evaluate the activity of a commercial (recombinant human) aldose reductase (ALR) used to catalyze the reduction of 2-keto-D-glucose (kDG) to fructose using NADPH as cofactor, by employing various enzyme/reactants
initial ratios. A kinetic model was proposed by extending the ‘core’ reaction mechanism proposed in literature for the reduction of several saccharides and keto-derivates (glucose, galactose, xylose, glyceraldehydes) by the human or animal ALR (wild or modified),
or by similar aldo-keto reductases (e.g. sorbitol dehydrogenase, xylose reductase) in the presence of NAD(P)H. The reaction pathway assumes a very quick reversible formation of a stable ALR•NADPH complex, from which a small fraction is binding the substrate thus determining a succession of Bi-Bi reversible reactions leading to the final product (fructose). Model parameters have been estimated based on the recorded data sets of four observable key-species, being in concordance with the reported values in literature for similar processes. The results confirm the conformational change of
E•NADP+ complex allowing the release of NADP+ as being the rate-limiting step of the overall process. The results also underline the necessity to stabilize the fast deactivating enzyme by immobilization, as well as the requirement of a continuous in-situ regeneration of the cofactor.
Ključne riječi
Keto-glucose reduction to fructose; aldose reductase; reaction mechanism; kinetic model
Hrčak ID:
112348
URI
Datum izdavanja:
19.12.2013.
Posjeta: 884 *