Abstract
Previous investigations have shown that the mitotic apparatus (MA) can be isolated from dividing sea urchin eggs in water buffered at pH 5.6 and that the addition of 1 M hexanediol to the solution raises the usable pH to 6.4. Long chain glycols appeared to be much more effective than related compounds in increasing the stability of the MA, and the aim of the investigations reported here was to determine the basis of this specificity. These experiments show that this impression of specificity is misleading and that under suitable experimental conditions a variety of compounds can be substituted for the glycols. A number of alcohols will duplicate the action of the glycols in stabilizing the MA at pH 6.4, but they must be used at a similar per cent concentration rather than at a similar molar concentration. Increases in the concentration of alcohol or glycol allow isolation at more alkaline pH values, and a pH-concentration relation for the stability of the MA, covering the range from pH 5.6–8, has been determined. These results indicate that the action of these compounds in stabilizing the mitotic apparatus is non-specific and is similar to their effects on the solubility of proteins. The isolation and stabilization of the mitotic apparatus can thus be viewed as a function of the solubility properties of its constituent proteins, opening a variety of new experimental approaches to this problem.
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Selected References
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- FRIGERIO N. A., HETTINGER T. P. Protein solubility in solvent mixtures of low dielectric constant. Biochim Biophys Acta. 1962 May 7;59:228–230. doi: 10.1016/0006-3002(62)90720-5. [DOI] [PubMed] [Google Scholar]
- MAZIA D., CHAFFEE R. R., IVERSON R. M. Adenosine triphosphatase in the mitotic apparatus. Proc Natl Acad Sci U S A. 1961 Jun 15;47:788–790. doi: 10.1073/pnas.47.6.788. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MAZIA D., MITCHISON J. M., MEDINA H., HARRIS P. The direct isolation of the mitotic apparatus. J Biophys Biochem Cytol. 1961 Aug;10:467–474. doi: 10.1083/jcb.10.4.467. [DOI] [PMC free article] [PubMed] [Google Scholar]
- MAZIA D. SH compounds in mitosis. I. The action of mercaptoethanol on the eggs of the sand dollar Dendraster excentricus. Exp Cell Res. 1958 Jun;14(3):486–494. doi: 10.1016/0014-4827(58)90156-3. [DOI] [PubMed] [Google Scholar]
- MAZIA D., ZIMMERMAN A. M. SH compounds in mitosis. II. The effect of mercaptoethanol on the structure of the mitotic apparatus in sea urchin eggs. Exp Cell Res. 1958 Aug;15(1):138–153. doi: 10.1016/0014-4827(58)90070-3. [DOI] [PubMed] [Google Scholar]
- Mazia D., Dan K. The Isolation and Biochemical Characterization of the Mitotic Apparatus of Dividing Cells. Proc Natl Acad Sci U S A. 1952 Sep;38(9):826–838. doi: 10.1073/pnas.38.9.826. [DOI] [PMC free article] [PubMed] [Google Scholar]
- ZIMMERMAN A. M. Physico-chemical analysis of the isolated mitotic apparatus. Exp Cell Res. 1960 Sep;20:529–547. doi: 10.1016/0014-4827(60)90122-1. [DOI] [PubMed] [Google Scholar]