Abstract
A homogenate from dwarf pea seedlings that had been treated with [3H]gibberellin A1 was separated by Sephadex G-200 into two protein fractions, of high and intermediate molecular weight, with affinity for [3H]gibberellin A1. Neither fraction bound [3H]gibberellin A8, the only metabolite of [3H]gibberellin A1 detected in significant quantity in extracts of pea seedlings. These proteinhormone complexes were noncovalently bound, as evidenced by their rapid disruption in ethanol. Approximate molecular weights of the fractions were 500,000 and 60,000. In experiments designed to detect competition for the binding proteins between [3H]gibberellin A1 and closely related [3H]gibberellin molecules, [3H]gibberellin A8 and pseudo [3H]gibberellin A1 were inactive, but keto [3H]gibberellin competed favorably. Equilibrium dialysis experiments revealed that both high-molecular-weight and intermediate-molecular-weight protein-hormone complexes could undergo hormone exchange with nonlabeled gibberellin A1.
Keywords: [3H]gibberellin A8, pseudo [3H]gibberellin A1, keto [3H]gibberellin A1
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Andrews P. Estimation of the molecular weights of proteins by Sephadex gel-filtration. Biochem J. 1964 May;91(2):222–233. doi: 10.1042/bj0910222. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Englund P. T., Huberman J. A., Jovin T. M., Kornberg A. Enzymatic synthesis of deoxyribonucleic acid. XXX. Binding of triphosphates to deoxyribonucleic acid polymerase. J Biol Chem. 1969 Jun 10;244(11):3038–3044. [PubMed] [Google Scholar]
- Gorell T. A., Gilbert L. I., Siddall J. B. Binding proteins for an ecdysone metabolite in the crustacean hepatopancreas. Proc Natl Acad Sci U S A. 1972 Apr;69(4):812–815. doi: 10.1073/pnas.69.4.812. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jensen E. V., Numata M., Brecher P. I., Desombre E. R. Hormone-receptor interaction as a guide to biochemical mechanism. Biochem Soc Symp. 1971;32:133–159. [PubMed] [Google Scholar]
- Johri M. M., Varner J. E. Enhancement of RNA synthesis in isolated pea nuclei by gibberellic acid. Proc Natl Acad Sci U S A. 1968 Jan;59(1):269–276. doi: 10.1073/pnas.59.1.269. [DOI] [PMC free article] [PubMed] [Google Scholar]