Naphthylphthalamic acid-binding sites in cultured cells from Nicotiana tabacum.
Planta
; 164(1): 69-74, 1985 May.
Article
in En
| MEDLINE
| ID: mdl-24249501
ABSTRACT
Naphthylphthalamic acid (NPA), an inhibitor of polar auxin transport, binds with high affinity to membrane preparations from callus and cell suspension cultures derived from Nicotiana tabacum (K d approx. 2·10(-9) M). The concentration of membrane-bound binding sites is higher in cell suspension than in callus cultures. The binding of NPA to these sites seems to be a simple process, in contrast to the binding of the synthetic auxin naphthylacetic acid (1-NAA) to membrane preparations from callus cultures, which is more complex (A.C. Maan et al., 1983, Planta 158, 10-15). Naphthylacetic acid, a number of structurally related compounds and the auxin-transport inhibitor triiodobenzoic acid were all able to compete with NPA for the same binding site with K d values ranging from 10(-6) to 10(-4) M. On the other hand, NPA was not able to displace detectable amounts of NAA from the NAA-binding site. A possible explantation is the existence of two different membrane-bound binding sites, one exclusively for auxins and one for NPA as well as auxins, that differ in concentration. The NPA-binding site is probably an auxin carrier.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
Planta
Year:
1985
Type:
Article
Affiliation country:
Netherlands