Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)

In isolated skinned crayfish muscle fibers bathed in solutions that were buffered to be virtually free of Ca(2+) (pCa 8–10) the substrate for both contraction and relaxation is the MgNTP complex. Tension increased up to 50% of the maximum capability of the fiber as the substrate MgATP increased to a...

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Autores principales: Reuben, J. P., Brandt, P. W., Berman, M., Grundfest, H.
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1971
Materias:
Article
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203112/
https://www.ncbi.nlm.nih.gov/pubmed/5549096
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author Reuben, J. P.
Brandt, P. W.
Berman, M.
Grundfest, H.
author_facet Reuben, J. P.
Brandt, P. W.
Berman, M.
Grundfest, H.
author_sort Reuben, J. P.
collection PubMed
description In isolated skinned crayfish muscle fibers bathed in solutions that were buffered to be virtually free of Ca(2+) (pCa 8–10) the substrate for both contraction and relaxation is the MgNTP complex. Tension increased up to 50% of the maximum capability of the fiber as the substrate MgATP increased to an optimum (pMgATP = 5.5). Relaxation was induced by further increases in MgATP. Similar bell-shaped curves of tension vs. pMgNTP were obtained with UTP and ITP, but optimum pMgUTP was about 4.5 and optimum pMgITP was about 2.6. The relation between equilibrium tension and pMgNTP is described by an equation analogous to that for the kinetics of enzymes regulated by substrate inhibition.
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spelling pubmed-22031122008-04-23 Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9) Reuben, J. P. Brandt, P. W. Berman, M. Grundfest, H. J Gen Physiol Article In isolated skinned crayfish muscle fibers bathed in solutions that were buffered to be virtually free of Ca(2+) (pCa 8–10) the substrate for both contraction and relaxation is the MgNTP complex. Tension increased up to 50% of the maximum capability of the fiber as the substrate MgATP increased to an optimum (pMgATP = 5.5). Relaxation was induced by further increases in MgATP. Similar bell-shaped curves of tension vs. pMgNTP were obtained with UTP and ITP, but optimum pMgUTP was about 4.5 and optimum pMgITP was about 2.6. The relation between equilibrium tension and pMgNTP is described by an equation analogous to that for the kinetics of enzymes regulated by substrate inhibition. The Rockefeller University Press 1971-04-01 /pmc/articles/PMC2203112/ /pubmed/5549096 Text en Copyright © 1971 by The Rockefeller University Press 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
Reuben, J. P.
Brandt, P. W.
Berman, M.
Grundfest, H.
Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title_full Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title_fullStr Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title_full_unstemmed Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title_short Regulation of Tension in the Skinned Crayfish Muscle Fiber : I. Contraction and relaxation in the absence of Ca (pCa > 9)
title_sort regulation of tension in the skinned crayfish muscle fiber : i. contraction and relaxation in the absence of ca (pca > 9)
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2203112/
https://www.ncbi.nlm.nih.gov/pubmed/5549096
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