Regulation of Tension in the Skinned Crayfish Muscle Fiber

Autor:	Harry Grundfest, John P. Reuben, Philip W. Brandt, M. Berman
Rok vydání:	1971
Předmět:	Contraction (grammar) Physiology Kinetics chemistry.chemical_element Calcium Crayfish chemistry.chemical_compound chemistry Biochemistry Biophysics medicine medicine.symptom Myofibril Adenosine triphosphate Uracil nucleotide Muscle contraction
Zdroj:	Journal of General Physiology. 57:385-407
ISSN:	1540-7748 0022-1295
DOI:	10.1085/jgp.57.4.385
Popis:	In isolated skinned crayfish muscle fibers bathed in solutions that were buffered to be virtually free of Ca2+ (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.
Databáze:	OpenAIRE
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