Abstract:
:A recent study showed that limited trypsin treatment of liposomes containing purified Electrophorus electricus sodium channels activates a sodium radiotracer flux. We now report that similarly treated sodium channels show voltage-gated, tetrodotoxin-sensitive and highly sodium-selective single-channel currents when incorporated into planar lipid membranes. The trypsinized channels opened repeatedly in bursts of several seconds duration, as would be expected for channels whose fast inactivation process had been removed. Furthermore, they have a higher conductance, different voltage-dependence of gating, and a remarkably higher selectivity (PNa/PK = 41) than sodium channels bound by batrachotoxin or other activating neurotoxins; these properties of the trypsinized channels are probably closer to those of channels in intact electrocytes.
journal_name
Proc Natl Acad Sci U S Aauthors
Shenkel S,Cooper EC,James W,Agnew WS,Sigworth FJdoi
10.1073/pnas.86.23.9592subject
Has Abstractpub_date
1989-12-01 00:00:00pages
9592-6issue
23eissn
0027-8424issn
1091-6490journal_volume
86pub_type
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