AJP - Cell Physiology, Vol 257, Issue 6 C1135-C1141, Copyright © 1989 by American Physiological Society
Distinct epitopes on amiloride
T. R. Kleyman, J. P. Kraehenbuhl, B. C. Rossier, E. J. Cragoe Jr and D. G. Warnock
Department of Medicine, University of Pennsylvania, Philadelphia 19104.
Most Na(+)-selective transport proteins are inhibited by the drug
amiloride. Studies using amiloride analogues suggest that specific regions
of amiloride might participate in binding to receptors on these transport
proteins. To determine whether certain domains of this drug are recognized
as distinct epitopes, amiloride was coupled to albumin through either its
C-5 NH2-group on the pyrazine ring or through a terminal NH2-group of the
guanidino moiety, and antibodies were raised against these
amiloride-albumin conjugates. Studies of antibody binding to amiloride
analogues identified the 3,5-diaminopyrazinyl, the guanidinocarbonyl, and
the C-6 halo moieties as distinct epitopes, although the antibodies
required the presence of both the 3,5-diaminopyrazinyl as well as the
guanidinocarbonyl moiety for binding.
