title: Role of metal ion free valinomycin-carbonyl cyanide m-chlorophenylhydrazone complex in the enhancement of the rates of gramicidin facilitated net H+, Li+ and Na+ transport across phospholipid vesicular membrane.
abstract: The studies on the decay of the pH difference, delta pH, across soyabean phospholipid vesicular membrane have shown that the rates of net proton transport and the associated Li+ and Na+ ion transport across the membrane can be enhanced by the combined action of gramicidin, valinomycin and carbonyl cyanide m-chlorophenylhydrazone (CCCP) in K(+)-free vesicle solutions. The data obtained under different experimental conditions suggest that this enhancement is a consequence of facilitation of CCCP- transport (1) by complexing CCCP- with the highly membrane permeant valinomycin without the metal ion bound to it and (2) by the associated Li+ or Na+ transport through the gramicidin channel such that no net charge is transported across the membrane. The dissociation constant of the weak valinomycin-CCCP- complex has been estimated to be > 200 mM in the membrane. The delta pH in these experiments were created by temperature jump.
authors.affiliation: Chemical Physics Group, Tata Institute of Fundamental Research, Mumbai, India.
authors.forename: B S
authors.initials: BS
authors.lastname: Prabhananda
authors.forename: M H
authors.initials: MH
authors.lastname: Kombrabail
mesh_terms: D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone / Q000378:metabolism*; D006096:Gramicidin / Q000378:metabolism*; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D017136:Ion Transport; D008094:Lithium / Q000378:metabolism; D008563:Membrane Lipids / Q000378:metabolism*; D010743:Phospholipids / Q000378:metabolism*; D011522:Protons; D012964:Sodium / Q000378:metabolism; D013696:Temperature; D014634:Valinomycin / Q000378:metabolism*
chemical_list: D008563:Membrane Lipids; D010743:Phospholipids; D011522:Protons; D006096:Gramicidin; D014634:Valinomycin; D002258:Carbonyl Cyanide m-Chlorophenyl Hydrazone; D008094:Lithium; D012964:Sodium