scholarly journals Temperature effect on isometric tension is mediated by regulatory proteins tropomyosin and troponin in bovine myocardium

2002 ◽  
Vol 539 (1) ◽  
pp. 267-276 ◽  
Author(s):  
Hideaki Fujita ◽  
Masataka Kawai
Keyword(s):  
Temperature Effect ◽  
Isometric Tension ◽  
Regulatory Proteins ◽  
Bovine Myocardium

scholarly journals Tropomyosin Period 3 Is Essential for Enhancement of Isometric Tension in Thin Filament-Reconstituted Bovine Myocardium

2009 ◽  
Vol 2009 ◽  
pp. 1-17 ◽  
Author(s):  
Masataka Kawai ◽  
Xiaoying Lu ◽  
Sarah E. Hitchcock-DeGregori ◽  
Kristen J. Stanton ◽  
Michael W. Wandling
Keyword(s):  
Thin Filament ◽  
Isometric Force ◽  
Isometric Tension ◽  
Kinetic Constants ◽  
Allosteric Effect ◽  
Fiber System ◽  
Period 2 ◽  
Cross Bridges ◽  
The Hill ◽  
Bovine Myocardium

Tropomyosin (Tm) consists of 7 quasiequivalent repeats known as “periods,” and its specific function may be associated with these periods. To test the hypothesis that either period 2 or 3 promotes force generation by inducing a positive allosteric effect on actin, we reconstituted the thin filament with mutant Tm in which either period 2 (Δ2Tm) or period 3 (Δ3Tm) was deleted. We then studied: isometric tension, stiffness, 6 kinetic constants, and the pCa-tension relationship. N-terminal acetylation of Tm did not cause any differences. The isometric tension in Δ2Tm remained unchanged, and was reduced to ~60% in Δ3Tm. Although the kinetic constants underwent small changes, the occupancy of strongly attached cross-bridges was not much different. The Hill factor (cooperativity) did not differ significantly between Δ2Tm (1.79 ± 0.19) and the control (1.73 ± 0.21), or Δ3Tm (1.35 ± 0.22) and the control. In contrast, pCa50 decreased slightly in Δ2Tm (5.11 ± 0.07), and increased significantly in Δ3Tm (5.57 ± 0.09) compared to the control (5.28 ± 0.04). These results demonstrate that, when ions are present at physiological concentrations in the muscle fiber system, period 3 (but not period 2) is essential for the positive allosteric effect that enhances the interaction between actin and myosin, and increases isometric force of each cross-bridge.

scholarly journals Elementary Steps of the Cross-Bridge Cycle in Bovine Myocardium with and without Regulatory Proteins

2002 ◽  
Vol 82 (2) ◽  
pp. 915-928 ◽  
Author(s):  
Hideaki Fujita ◽  
Daisuke Sasaki ◽  
Shin’ichi Ishiwata ◽  
Masataka Kawai
Keyword(s):  
Regulatory Proteins ◽  
Elementary Steps ◽  
Cross Bridge ◽  
The Cross ◽  
Bovine Myocardium

Toward an alignment of the actin molecule within the actin filament

1983 ◽  
Vol 41 ◽  
pp. 450-451
Author(s):  
P.R. Smith ◽  
W.E. Fowler ◽  
U. Aebi
Keyword(s):  
Actin Filament ◽  
Diffraction Data ◽  
Quantitative Estimate ◽  
Molecular Model ◽  
Quantitative Comparison ◽  
Regulatory Proteins ◽  
Essential Information ◽  
X Ray ◽  
Maximum Resolution ◽  
Lack Of Information

An understanding of the specific interactions of actin with regulatory proteins has been limited by the lack of information about the structure of the actin filament. Molecular actin has been studied in actin-DNase I complexes by single crystal X-ray analysis, to a resolution of about 0.6nm, and in the electron microscope where two dimensional actin sheets have been reconstructed to a maximum resolution of 1.5nm. While these studies have shown something of the structure of individual actin molecules, essential information about the orientation of actin in the filament is still unavailable.The work of Egelman & DeRosier has, however, suggested a method which could be used to provide an initial quantitative estimate of the orientation of actin within the filament. This method involves the quantitative comparison of computed diffraction data from single actin filaments with diffraction data derived from synthetic filaments constructed using the molecular model of actin as a building block. Their preliminary work was conducted using a model consisting of two juxtaposed spheres of equal size.

Analysis of the high temperature effect in conical nozzle

2017 ◽  
Author(s):  
João Felipe de Araujo Martos ◽  
Paulo Toro ◽  
Israel Rêgo ◽  
sergio nicolás pachón laitón ◽  
Bruno Coelho Lima
Keyword(s):  
High Temperature ◽  
Temperature Effect ◽  
Conical Nozzle ◽  
High Temperature Effect

TEMPERATURE EFFECT ON MICROSTRUCTURAL ANALYSIS OF STEEL DURING HEAT TREATMENT

2020 ◽  
Author(s):  
SAMUEL BRITO ◽  
RODOLFO SOBRAL ◽  
Luiz Carlos Sacramento ◽  
Marcos Paulo de Souza Junior
Keyword(s):  
Heat Treatment ◽  
Temperature Effect ◽  
Microstructural Analysis
Sign in / Sign up

Export Citation Format

Share Document