OmpF of Escherichia coli in 1 M NaCl 0.8: major porin from Rhodopseudomonas blastica in 1 M KCl 3.9 nanosiemens
||Arora A, Rinehart D, Szabo G, Tamm LK. Refolded outer membrane protein A of Escherichia coli forms ion channels with two conductance states in planar lipid bilayers. J Biol Chem. 2000 Jan 21 275(3):1594-600. p.1594 right column top paragraphPubMed ID10636850
|| Phale PS et al., Voltage gating of Escherichia coli porin channels: role of the constriction loop. Proc Natl Acad Sci U S A. 1997 Jun 24 94(13):6741-5.  Schmid B et al., Porin mutants with new channel properties. Protein Sci. 1998 Jul7(7):1603-11.PubMed ID9192635, 9684893
||P.1594 right column top paragraph:"The substrate specificity of these proteins [outer membrane proteins] arises from specific residues in the pore, special peptide segments (aromatic “greasy slide” in LamB), or entire protein domains (periplasmic “cork” in FhuA). When incorporated into black lipid membranes, porins exhibit single channel activities that strongly depend on the particular porin, the applied transmembrane potential, and the type and concentration of the electrolyte in the environment. For example, OmpF of Escherichia coli has a conductance of 0.8 nanosiemens in 1M NaCl, whereas the major porin from Rhodopseudomonas blastica, which is of similar size, exhibits a conductance of 3.9 nanosiemens in 1M KCl (primary sources)."