What question did this study set out to answer?

To characterize the mechanism, reversal frequency, and oxygen equivalence of myosin-catalyzed phosphate oxygen exchange reactions using oxygen-18 labeling.

August 1, 1978Journal of Biological ChemistryOpen Access

Characterization of phosphate oxygen exchange reactions catalyzed by myosin through measurement of the distribution of 18-O-labeled species

View Full Paper

Ask AI

Bookmark

Authors

JSJohn SleepUniversity of Exeter DHDavid D. HackneyNorthwestern University PBPaul D. BoyerKettering Foundation

Discussion

Member takes

Implication

In vitro kinetic study uncovers extensive oxygen exchange reversals during myosin-catalyzed ATP hydrolysis, indicating equivalent participation of all four phosphate oxygens.

Key Points

To characterize the mechanism, reversal frequency, and oxygen equivalence of myosin-catalyzed phosphate oxygen exchange reactions using oxygen-18 labeling.
Measured the distribution of phosphate species with 0 to 4 oxygen-18 atoms during medium Pi equilibrium water exchange catalyzed by myosin subfragment 1 at 25 °C and 0 °C.
Analyzed intermediate oxygen exchange during the hydrolysis of oxygen-18-labeled ATP by myosin preparations.
Bound Pi lost an average of 3.9 of its 4 oxygens prior to release at 25 °C (≥100 reversals) and 3.4 of 4 oxygens at 0 °C (~17 reversals).
Isotopic distribution patterns confirmed equivalent participation of all four bound phosphate oxygens in the exchange reaction.
Identified a contaminating ATPase that hydrolyzes ATP without intermediate exchange, correcting for which aligns myosin intermediate exchange kinetics with subfragment 1 data.

Cite This Study

Sleep et al. (1978) studied this question.

synapsesocial.com/papers/6a879ca0de86c48a687d6534 https://doi.org/10.1016/s0021-9258(17)30354-x

View Full Paper

Ask AI

Bookmark

Implication

In vitro kinetic study uncovers extensive oxygen exchange reversals during myosin-catalyzed ATP hydrolysis, indicating equivalent participation of all four phosphate oxygens.

Characterization of phosphate oxygen exchange reactions catalyzed by myosin through measurement of the distribution of 18-O-labeled species

Discussion

Member takes

Implication

Key Points

Cite This Study

Characterization of phosphate oxygen exchange reactions catalyzed by myosin through measurement of the distribution of 18-O-labeled species

Discussion

Member takes

Implication

Key Points

Cite This Study

Also Consider

Also Consider