What is the true ATPase activity of contracting myofibrils?

Houadjeto, Maurice; Barman, Tom; Travers, Franck

doi:10.1016/0014-5793(91)80369-e

Cited by 20 publications

(31 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Our working hypothesis is that fibres contracting rapidly under zero load are modeled by activated myofibrils [3] and isometric fibres by crosslinked myofibrils [5]. Here we have shown that AM" ADP.…”

Section: Discussionmentioning

confidence: 99%

“…Although there have been several studies of the myofibrillar ATPases [3][4][5][6][7], these were confned to the early steps of the pathway, i.e. the binding and hydrolysis of ATP (steps 1 and 2 in Scheme 1).…”

Section: Discussionmentioning

confidence: 99%

“…With myofibrils, force measurements have been carried out [1,2] and their chemical kinetics have been studied in detail (e.g. [3][4][5][6][7]). For the interpretation of the kinetics we consider a condensed version of the mechanism, adapted to the studies presented here and shown in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Time resolved measurements show that phosphate release is the rate limiting step on myofibrillar ATPases

Lionne

Brüne²,

Webb³

et al. 1995

FEBS Letters

Self Cite

View full text Add to dashboard Cite

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Time resolved measurements show that phosphate release is the rate limiting step on myofibrillar ATPases

Lionne

Brüne²,

Webb³

et al. 1995

FEBS Letters

Self Cite

View full text Add to dashboard Cite

“…Using this method, myofibril suspensions are rapidly mixed with ATP and then quenched at different times with acid to determine the time course of [P i ] produced by ATP hydrolysis [57,90,92,98].…”

Section: Troponin Regulatory Kineticsmentioning

confidence: 99%

Insights into the kinetics of Ca2+-regulated contraction and relaxation from myofibril studies

Stehle

Solzin

Iorga

et al. 2009

Pflugers Arch - Eur J Physiol

View full text Add to dashboard Cite

Muscle contraction results from force-generating interactions between myosin cross-bridges on the thick filament and actin on the thin filament. The force-generating interactions are regulated by Ca(2+) via specialised proteins of the thin filament. It is controversial how the contractile and regulatory systems dynamically interact to determine the time course of muscle contraction and relaxation. Whereas kinetics of Ca(2+)-induced thin-filament regulation is often investigated with isolated proteins, force kinetics is usually studied in muscle fibres. The gap between studies on isolated proteins and structured fibres is now bridged by recent techniques that analyse the chemical and mechanical kinetics of small components of a muscle fibre, subcellular myofibrils isolated from skeletal and cardiac muscle. Formed of serially arranged repeating units called sarcomeres, myofibrils have a complete fully structured ensemble of contractile and Ca(2+) regulatory proteins. The small diameter of myofibrils (few micrometres) facilitates analysis of the kinetics of sarcomere contraction and relaxation induced by rapid changes of [ATP] or [Ca(2+)]. Among the processes studied on myofibrils are: (1) the Ca(2+)-regulated switch on/off of the troponin complex, (2) the chemical steps in the cross-bridge adenosine triphosphatase cycle, (3) the mechanics of force generation and (4) the length dynamics of individual sarcomeres. These studies give new insights into the kinetics of thin-filament regulation and of cross-bridge turnover, how cross-bridges transform chemical energy into mechanical work, and suggest that the cross-bridge ensembles of each half-sarcomere cooperate with each other across the half-sarcomere borders. Additionally, we now have a better understanding of muscle relaxation and its impairment in certain muscle diseases.

show abstract

“…Thus, the fragile fatty acid synthetase complex was studied successfully by QF after appropriate measures had been taken [55]. Myofibrils are fibrous structures (typically 1 µm diameter and 30 µm length) that appear not to be damaged when mixed with buffer in a QF apparatus [56] and several studies have been carried out on their ATPases (ref. 57 and references cited therein].…”

Section: Further Qf Studiesmentioning

confidence: 99%

The identification of chemical intermediates in enzyme catalysis by the rapid quench-flow technique

Barman

Bellamy

Gutfreund

et al. 2006

Cell. Mol. Life Sci.

View full text Add to dashboard Cite

Traditionally, enzyme transient kinetics have been studied by the stopped-flow and rapid quench-flow (QF) methods. Whereas stopped-flow is the more convenient, it suffers from two weaknesses: optically silent systems cannot be studied, and when there is a signal it cannot always be assigned to a particular step in the reaction pathway. QF is a chemical sampling method; reaction mixtures are aged for a few milliseconds or longer, 'stopped' by a quenching agent and the product or the intermediate is measured by a specific analytical method. Here we show that by exploiting the array of current analytical methods and different quenching agents, the QF method is a key technique for identifying, and for characterising kinetically, intermediates in enzyme reaction pathways and for determining the order by which bonds are formed or cleaved by enzymes acting on polymer substrates such as DNA.

show abstract

What is the true ATPase activity of contracting myofibrils?

Abstract: Abbreviurio~r: Sl, myosin subfragment IPublished by Elsevier Science Publishers B. V.

Cited by 20 publications

References 14 publications

Time resolved measurements show that phosphate release is the rate limiting step on myofibrillar ATPases

Time resolved measurements show that phosphate release is the rate limiting step on myofibrillar ATPases

Insights into the kinetics of Ca2+-regulated contraction and relaxation from myofibril studies

The identification of chemical intermediates in enzyme catalysis by the rapid quench-flow technique

Contact Info

Product

Resources

About