Inhibition of halobacterial Na+/H(+)-antiporter by carboxyl modifying reagent, EEDQ.
The Inhibitory effect of N-ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ), a hydrohobic carboxyl modifying reagent, on the N,N'-dicyclohexylcarbodiimide (DCCD)-sensitive Na+/H(+)-antiporter in Archaebacterial H. halobium, was studied. The inhibition time course suggests that a single carboxyl residue is modified by EEDQ. The profile of pH dependence of EEDQ effect and the competitive binding of [14C]-DCCD and EEDQ indicate that EEDQ does not compete with DCCD for the same site but modifies one of the two functional H+ binding sites previously reported [Murakami and Konishi (1989) Arch. Biochem. Biophys. 271, 515-523].
Niwano
K
K
Department of Radiochemistry-Biophysics, Niigata College of Pharmacy, Japan.
Murakami
N
N
Okazawa
K
K
Konishi
T
T
D001665:Binding Sites; D001667:Binding, Competitive; D002352:Carrier Proteins / Q000037:antagonists & inhibitors*; D004024:Dicyclohexylcarbodiimide / Q000378:metabolism / Q000494:pharmacology; D019617:Halobacterium salinarum / Q000187:drug effects / Q000378:metabolism*; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008027:Light; D008564:Membrane Potentials / Q000187:drug effects; D011804:Quinolines / Q000378:metabolism / Q000494:pharmacology*; D012964:Sodium / Q000378:metabolism; D017923:Sodium-Hydrogen Exchangers
D002352:Carrier Proteins; D011804:Quinolines; D017923:Sodium-Hydrogen Exchangers; D004024:Dicyclohexylcarbodiimide; C000470:EEDQ; D006859:Hydrogen; D012964:Sodium