We report on the use of poly
myxin (PM), a cyclic cationic lipodecapeptide, as an electrode
modifier for studying protein fil
m volta
mmetry (PFV) on Au and single-walled carbon nanotube (SWNT) electrodes. Pretreating the electrodes with PM allows for the subsequent i
mmobilization of an active sub
monolayer of [NiFe]-hydrogenase fro
m Allochromatium vinosum (
Av H
2ase). Probed by cyclic volta
mmetry (CV), the adsorbed enzy
me exhibits characteristic electrocatalytic behavior that is stable for several hours under continuous potential cycling. An unexpected feature of the i
mmobilization procedure is that the presence of chloride ions is a prerequisite for obtaining electrocatalytic activity. Ato
mic force
microscopy (AFM) relates the observed catalytic activity to enzy
matic adsorption at the PM/Au(111) surface, and a co
mbination of concentration-dependent CV and AFM is used to investigate the interaction between the enzy
me and the PM layer.
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