INVESTIGADORES
CALVO Ernesto Julio
artículos
Título:
Electrochemical behavior of polyphenol oxidase immobilized in self-assembled structures layer by layer with cationic polyallylamine
Autor/es:
FORZANI, E. S; SOLIS, V. M; ERNESTO JULIO CALVO
Revista:
Analytical Chemistry (Washington)
Referencias:
Año: 2000 vol. 72 p. 5300 - 5307
Resumen:
We report here a novel bioelectrode based on selfassembled
multilayers of polyphenol oxidase intercalated
with cationic polyallylamine built up on a thiol-modified
gold surface. We use an immobilization strategy previously
described by Hodak J. et al. (Langmuir 1997, 13,
2708-2716) Quartz crystal microbalance with electroacustic
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
2708-2716) Quartz crystal microbalance with electroacustic
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
Langmuir 1997, 13,
2708-2716) Quartz crystal microbalance with electroacustic
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
-2716) Quartz crystal microbalance with electroacustic
impedance experiments were carried out to follow
quantitatively the multilayer film formation. The response
of the self-assembly polyphenol oxidase-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
-polyallylamine
electrodes toward different metabolically related catecholamines
was studied, to evaluate enzyme kinetics. For
the analyzed compounds, only dopamine and its metabolite
Dopac gave catalytic currents at applied potential close
to 0 V. These responses were proportional to the number
of polyphenol oxidase-immobilized layers and were also
controlled by the enzymatic reaction. The combination of
microgravimetric and electrochemical techniques allowed
us to determine the kinetic enzymatic constants, showing
that the decomposition rate for the enzyme-substrate
complex is slower than the enzymatic reoxidation step.
complex is slower than the enzymatic reoxidation step.
-substrate
complex is slower than the enzymatic reoxidation step.