Kinetics and mechanism of heterogeneous hydrolysis of poly[(R)-3-hydroxybutyrate]fielm by PHA depolymerases
Kinetics and mechanism of heterogeneous hydrolysis of poly[(R)-3-hydroxybutyrate]fielm by PHA depolymerases
- Int. J. Biol. Macromol., 15(6), p.361-366, 1993 .
The kinetics and mechanism of enzymatic degradation on the surface of poly[(R)-3-hydroxybutyrate](PC(R)-3HB]) jilm have been studied using three types of extracellular poly(hydroxyalkanoate)(PHA)depolymerases from Alcaligenes faecalis, Pseudomonas pickettii and Comamonas testosteroni. The monomer and dimer of 3-hydroxybutyric acid were produced during the course of the enzymatic degradation of PC(R)-3HB]film, and the rate of production was determined by monitoring the increase in absorbance at 210 nm on a spectrophotometer. The rate of enzymatic degradation increased to a maximum value with the concentration of PHA depolymerase, followed by a gradual decrease. The kinetic data were accountedfor in terms of a heterogeneous enzymatic reaction, involving enzymatic degradation on the surface of PC(R)-3HB]jilm via two steps of adsorption and hydrolysis by a PHA depolymerase with binding and catalytic domains. The kinetic results suggest that the properties oj-the catalytic domains are very similar among the three PHA depolymerases, but that those of the binding domains are strongly dependent on the type of depolymerase.
ENZYMATIC DEGRADATION
PHA DEPOLYMERASES
POLY[(R)-3-HYDROXYBUTYRATE]
HETEROGENEOUS HYDROLYSIS
KINETIC MODEL
The kinetics and mechanism of enzymatic degradation on the surface of poly[(R)-3-hydroxybutyrate](PC(R)-3HB]) jilm have been studied using three types of extracellular poly(hydroxyalkanoate)(PHA)depolymerases from Alcaligenes faecalis, Pseudomonas pickettii and Comamonas testosteroni. The monomer and dimer of 3-hydroxybutyric acid were produced during the course of the enzymatic degradation of PC(R)-3HB]film, and the rate of production was determined by monitoring the increase in absorbance at 210 nm on a spectrophotometer. The rate of enzymatic degradation increased to a maximum value with the concentration of PHA depolymerase, followed by a gradual decrease. The kinetic data were accountedfor in terms of a heterogeneous enzymatic reaction, involving enzymatic degradation on the surface of PC(R)-3HB]jilm via two steps of adsorption and hydrolysis by a PHA depolymerase with binding and catalytic domains. The kinetic results suggest that the properties oj-the catalytic domains are very similar among the three PHA depolymerases, but that those of the binding domains are strongly dependent on the type of depolymerase.
ENZYMATIC DEGRADATION
PHA DEPOLYMERASES
POLY[(R)-3-HYDROXYBUTYRATE]
HETEROGENEOUS HYDROLYSIS
KINETIC MODEL