What question did this study set out to answer?

To investigate the enthalpy changes associated with each intermediate step of ATP hydrolysis catalyzed by myosin subfragment-1.

July 1, 1979Journal of Biological ChemistryOpen Access

Enthalpy changes for intermediate steps of the ATP hydrolysis catalyzed by myosin subfragment-1.

View Full Paper

Ask AI

Bookmark

Population

Myosin subfragment-1 in 0.1 M KCl containing 0.01 M MgCl2 and 0.02 M Tris/HCl (pH 7.8) at 23°C

Comparison

ATP hydrolysis catalyzed by myosin subfragment-1 vs ATP hydrolysis in free solution

Design

Preclinical

Authors

TKToshio KodamaNagasaki University RWR. C. WoledgeKing's College London

Discussion

Member takes

Implication

Thermodynamic profiles of myosin ATPase steps refine contraction energetics models; extends biochemical understanding but leaves in vivo cardiac relevance open.

Key Points

To investigate the enthalpy changes associated with each intermediate step of ATP hydrolysis catalyzed by myosin subfragment-1.
Microcalorimetry was used to measure heat production during ATP hydrolysis in 0.1 M KCl with 0.01 M MgCl2 and 0.02 M Tris/HCl (pH 7.8) at 23°C.
Enthalpy values for ATP binding, cleavage, and product release were determined and compared with values in free solution.
Binding of ATP to Subfragment 1 is exothermic (enthalpy change = -90 kJ/mol).
Cleavage of ATP is endothermic (enthalpy change = +83 kJ/mol), contrary to the exothermic nature of free solution ATP hydrolysis.
Pi release is strongly exothermic (enthalpy change = -88 kJ/mol), while dissociation of ADP is endothermic (enthalpy change = +72 kJ/mol).

Structured PICO

Population

Myosin subfragment-1 in 0.1 M KCl containing 0.01 M MgCl2 and 0.02 M Tris/HCl (pH 7.8) at 23°C

Intervention

ATP hydrolysis catalyzed by myosin subfragment-1

Comparator

ATP hydrolysis in free solution

Outcome

Enthalpy changes (heat production) during intermediate steps of ATP hydrolysissurrogate

Large enthalpy changes accompany several intermediate steps of the myosin-catalyzed ATP hydrolysis cycle, reflecting its energy transduction role in muscle contraction.

Cite This Study

Kodama et al. (1979) studied this question.

synapsesocial.com/papers/6a216864cdf8429e7e5fa46b https://doi.org/10.1016/s0021-9258(18)50376-8

View Full Paper

Ask AI

Bookmark

Implication

Thermodynamic profiles of myosin ATPase steps refine contraction energetics models; extends biochemical understanding but leaves in vivo cardiac relevance open.

Enthalpy changes for intermediate steps of the ATP hydrolysis catalyzed by myosin subfragment-1.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Enthalpy changes for intermediate steps of the ATP hydrolysis catalyzed by myosin subfragment-1.

Discussion

Member takes

Implication

Key Points

Structured PICO

Cite This Study

Also Consider

Also Consider