TY - JOUR
T1 - Modelling the enzymatic deacylation of penicillin G
T2 - Equilibrium and kinetic considerations
AU - Van Der Wielen, L. A.M.
AU - Van Buel, M. J.
AU - Straathof, A. J.J.
AU - Luyben, K. Ch A.M.
PY - 1997
Y1 - 1997
N2 - The equilibrium position and kinetics of the enzymatic hydrolysis of penicillin G are complex functions of the thermodynamic state of the reaction system. It is desirable to describe the equilibrium position and the course of the deacylation reaction using a consistent basis, preferably with one single set of parameters. Taking the weak electrolytic nature of the reactants into account, an equilibrium model has been derived which incorporates the effects of thermodynamic non-ideality in terms of electrostatic interactions only. The effects of ionic strength can be described within the experimental error. Multiple ionic forms of the reactants coexist, of which one is assumed to be the actual reacting species. A mechanistic kinetic model has been developed which takes the fraction of this species into account. When the anionic forms of the reactants were assumed to be the actual reacting species, the best description of the experimental curves was obtained. However, when compared to a model which takes overall concentrations into account, the improvement is very modest because in the relevant pH-interval, the reactants remain primarily anionic. Using the fully anionic framework, the model has a broad range of validity in terms of reactant concentrations and pH-values and may be applied for the optimization of industrial deacylation reactors.
AB - The equilibrium position and kinetics of the enzymatic hydrolysis of penicillin G are complex functions of the thermodynamic state of the reaction system. It is desirable to describe the equilibrium position and the course of the deacylation reaction using a consistent basis, preferably with one single set of parameters. Taking the weak electrolytic nature of the reactants into account, an equilibrium model has been derived which incorporates the effects of thermodynamic non-ideality in terms of electrostatic interactions only. The effects of ionic strength can be described within the experimental error. Multiple ionic forms of the reactants coexist, of which one is assumed to be the actual reacting species. A mechanistic kinetic model has been developed which takes the fraction of this species into account. When the anionic forms of the reactants were assumed to be the actual reacting species, the best description of the experimental curves was obtained. However, when compared to a model which takes overall concentrations into account, the improvement is very modest because in the relevant pH-interval, the reactants remain primarily anionic. Using the fully anionic framework, the model has a broad range of validity in terms of reactant concentrations and pH-values and may be applied for the optimization of industrial deacylation reactors.
KW - 6-aminopenicillanic acid
KW - Electrolytes
KW - Kinetics
KW - Penicillin G acylase
KW - Phenylacetic acid
KW - Thermodynamics
UR - http://www.scopus.com/inward/record.url?scp=0031432682&partnerID=8YFLogxK
U2 - 10.3109/10242429709003614
DO - 10.3109/10242429709003614
M3 - Article
AN - SCOPUS:0031432682
SN - 1024-2422
VL - 15
SP - 121
EP - 146
JO - Biocatalysis and Biotransformation
JF - Biocatalysis and Biotransformation
IS - 2
ER -