Summary
Detailed examination of binding over the range 10-7–10-6 M suggests that membrane preparations from coleoptiles of Zea mays L., cv Kelvedon 33 contain at least two sets of high affinity binding sites for 1-naphthylacetic acid (NAA), with dissociation constants of 1.8×10-7 M (site 1) and 14.5×10-7 M (site 2). Similar studies with 3-indolylacetic acid (IAA) also indicate two sets of binding sites, whose concentrations are closely comparable to those deduced for NAA. A substantial proportion of the total binding activity is retained in a detergent-solubilized preparation. Using [14C]NAA the interactions of a range of analogues with each of the binding sites have been examined with the aid of double reciprocal plots. The specificity of site 2 is compatible with that expected for an auxin receptor, in that only active auxins, antiauxin transport inhibitors are able to compete with [14C]NAA for the binding sites. Site 1 on the other hand is less specific, since it appears to bind all compounds tested, including physiologically inactive analogues.
Similar content being viewed by others
Abbreviations
- NAA:
-
1-naphthylacetic acid
- IAA:
-
3-indolylacetic acid
- 2,4-D:
-
2,4-dichlorophenoxyacetic acid
- 2,6-D:
-
2,6-dichlorophenoxyacetic acid
- 2,4,5-T:
-
2,4,5-trichlorophenoxyacetic acid
- 2-CPIB:
-
α-(2-chlorophenoxy)-isobutyric acid
- 2,4-B:
-
2,4-dichlorobenzoic acid
- 2,6-B:
-
2,6-dichlorobenzoic acid
- TIBA:
-
2,3,5-triiodobenzoic acid
- NPA:
-
1-N-naphthylphthalamic acid
References
Dixon, M., Webb, E.C.: Enzymes. London: Longman's, Green 1958
Evans, M.L.: Rapid responses to plant hormones. Ann. Rev. Plant Physiol. 25, 195–224 (1974)
Hertel, R.: Auxin transport and in vitro binding. In: Membrane transport in plants. Zimmermann, V., Dainty, J. (Eds.), pp. 457–461. Berlin-Heidelberg-New York: Springer 1974
Hertel, R., Thomson, K., Russo, V.E.A.: In vitro auxin binding to particulate cell fractions from corn coleoptiles. Planta (Berl.) 107, 325–340 (1972)
Hunston, D.L.: Two techniques for evaluating small moleculemacromolecule binding in complex systems. An. Biochem. 63, 99–109 (1975)
Jönsson, A.: Chemical structure and growth activity of auxins and anti-auxins. In: Encyclopedia of Plant Physiology. Ruhland, W. (Ed.), Vol. XIV, pp. 995–1006. Berlin-Göttingen-Heidelberg: Springer 1961
Klotz, I.M.: Protein interactions. In: The proteins. Neurath, H., Bailey, K. (Eds.), Vol. 1B, 1st Ed., pp. 727–806. New York: Academic Press 1953
Lembi, C.A., Morré, D.J., Thomson, K.S., Hertel, R.: N-1-naphthylphthalamic acid binding activity of a plasma membrane-rich fraction from maize coleoptiles. Planta (Berl.) 99, 37–45 (1971)
Osborne, D.J., Blackman, G.E., Powell, R.G., Sudzuki, F., Novoa, S.: Growth-regulating activity of certain 2:6-substituted phenoxyacetic acids. Nature 174, 742 (1954)
Scatchard, G.: The attractions of proteins for small molecules and ions. Ann. N. Y. Acad. Sci. 51, 660–672 (1949)
Thomson, K.-S.: The binding of N-1-naphthylphthalamic acid (NPA), an inhibitor of auxin transport, to particulate fractions of corn coleoptiles. In: Hormonal regulation in plant fractions and development. Kaldewey, H., Vardar, Y. (Eds.), pp. 83–88. Weinheim: Verlag Chemie 1972
Thomson, K.-S., Hertel, R., Muller, S., Tavares, J.E.: 1-N-naphthylphthalamic acid and 2,3,5-triiodobenzoic acid. In vitro binding to particulate cell fractions and action on auxin transport in corn coleoptiles. Planta (Berl.) 199, 337–352 (1973)
Wilkinson, G.: Statistical estimations in enzyme kinetics. Biochem. J. 80, 324–332 (1961)
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Batt, S., Wilkins, M.B. & Venis, M.A. Auxin binding to corn coleoptile membranes: Kinetics and specificity. Planta 130, 7–13 (1976). https://doi.org/10.1007/BF00390838
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00390838