Electrochemical Analysis of Ion Channels and Transporters in Pore-Suspending Membranes - Applications of Electrochemistry and Nanotechnology in Biology and Medicine - page 317

A

150

100

50

(+PM)

0

(-PM)

-50

0 1 2 3 4 5 6

t / s

1.0

B

0.8

0.6

0.4

0.2

0.0

450 500 550 600 650

/ nm

Figure 18. A) Photocurrent before (- PM) and after (+ PM) addi-
tion of purple membranes to the cis compartment. (+ PM) The first
transient corresponds to switching the light on, the second transient
to switching the light off. The current was recorded 40 min after
addition of purple membranes to a nano-BLM. (- PM) The current
trace corresponds to the signal recorded before addition of purple
membranes. No significant photoartefact can be detected. For clari-
ty, the current trace is shifted by -50 nA cm -2 . B) Action spectrum
of bR. The action spectrum is represented as the normalized peak
current density. The dashed line is a Gaussian function fit to the
spectrum. A peak maximum of O max = 548 nm is obtained. For
comparison, the absorption spectrum of purple membranes in solu-
tion was measured (solid line). The characteristic maximum ab-
sorbance of bR was found at 568 nm. 107