Imagine you have extracted myosin molecules from both fast and slow twitch muscle fibers and are measuring the rate at which these proteins hydrolyze ATP.What would these relative rates of ATP hydrolysis be?
A)fast twitch fiber slow twitch fiber
B)slow twitch fiber fast twitch fiber
C)slow twitch fiber = fast twitch fiber

Question

Imagine you have extracted myosin molecules from both fast and slow twitch muscle fibers and are measuring the rate at which these proteins hydrolyze ATP.What would these relative rates of ATP hydrolysis be?
A)fast twitch fiber > slow twitch fiber
B)slow twitch fiber > fast twitch fiber
C)slow twitch fiber = fast twitch fiber

Quizplus · Accepted Answer

Fast twitch muscle fibers have a higher concentration of myosin isoform II compared to slow twitch muscle fibers. Myosin II has a higher rate of ATP hydrolysis than myosin I isoform found in slow twitch muscle fibers. Therefore, the relative rate of ATP hydrolysis will be higher in fast twitch muscle fibers compared to slow twitch muscle fibers.

Imagine You Have Extracted Myosin Molecules from Both Fast and Slow