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Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium
Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation...
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Formato: | Texto |
Lenguaje: | English |
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The Rockefeller University Press
1974
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203556/ https://www.ncbi.nlm.nih.gov/pubmed/4856294 |
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author | Nakamura, Masahisa Yasumasu, Ikuo |
author_facet | Nakamura, Masahisa Yasumasu, Ikuo |
author_sort | Nakamura, Masahisa |
collection | PubMed |
description | Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation constant between free calcium (dialyzable calcium) and homogenate of sea urchin eggs was measured by means of dialysis equilibrium. The dissociation constant of the unfertilized egg was about 10(–4) M and that of the fertilized egg was about 10–3 M in three species of sea urchin, Hemicentrotus pulcherrimus, Anthocidaris crassispina, and Pseudocentrotus depressus. An increase in the dissociation constant of the unfertilized egg homogenate was observed after the addition of calcium ion at a concentration above 0.3 mM, the dissociation constant becoming the same as that observed in the fertilized egg homogenate after the administration of CaCl(2) at a concentration above 1 mM. Sodium ion also caused a decrease in the calcium-binding ability of the unfertilized egg homogenate. Therefore, penetration of calcium ion or sodium ion upon fertilization might induce an increase in the dissociation constant and then intracellular concentration of free calcium would increase at fertilization. Almost all calcium-binding ability of the egg homogenate was found in the microsomal fraction, and the substance which bound calcium was thought to be protein in nature, since trypsin could decrease the level of calcium-binding substance in the homogenate of the eggs. |
format | Text |
id | pubmed-2203556 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 1974 |
publisher | The Rockefeller University Press |
record_format | MEDLINE/PubMed |
spelling | pubmed-22035562008-04-23 Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium Nakamura, Masahisa Yasumasu, Ikuo J Gen Physiol Article Intracellular free calcium concentration in the sea urchin egg was calculated to increase from 0.1 mM in an unfertilized egg to 1 mM in a fertilized egg 10 min after fertilization, based on measurement of the dissociation constant between free calcium and sea urchin egg homogenate. The dissociation constant between free calcium (dialyzable calcium) and homogenate of sea urchin eggs was measured by means of dialysis equilibrium. The dissociation constant of the unfertilized egg was about 10(–4) M and that of the fertilized egg was about 10–3 M in three species of sea urchin, Hemicentrotus pulcherrimus, Anthocidaris crassispina, and Pseudocentrotus depressus. An increase in the dissociation constant of the unfertilized egg homogenate was observed after the addition of calcium ion at a concentration above 0.3 mM, the dissociation constant becoming the same as that observed in the fertilized egg homogenate after the administration of CaCl(2) at a concentration above 1 mM. Sodium ion also caused a decrease in the calcium-binding ability of the unfertilized egg homogenate. Therefore, penetration of calcium ion or sodium ion upon fertilization might induce an increase in the dissociation constant and then intracellular concentration of free calcium would increase at fertilization. Almost all calcium-binding ability of the egg homogenate was found in the microsomal fraction, and the substance which bound calcium was thought to be protein in nature, since trypsin could decrease the level of calcium-binding substance in the homogenate of the eggs. The Rockefeller University Press 1974-03-01 /pmc/articles/PMC2203556/ /pubmed/4856294 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/). |
spellingShingle | Article Nakamura, Masahisa Yasumasu, Ikuo Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title | Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title_full | Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title_fullStr | Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title_full_unstemmed | Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title_short | Mechanism for Increase in Intracellular Concentration of Free Calcium in Fertilized Sea Urchin Egg : A Method for Estimating Intracellular Concentration of Free Calcium |
title_sort | mechanism for increase in intracellular concentration of free calcium in fertilized sea urchin egg : a method for estimating intracellular concentration of free calcium |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203556/ https://www.ncbi.nlm.nih.gov/pubmed/4856294 |
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