How is Ras activity turned off?
A)It is turned off by phosphorylation.
B)It is turned off by hydrolysis of its bound GTP to GDP.
C)It is turned off by hydrolysis of its bound GDP to GTP.
D)It is turned off by an allosteric inhibitor.
E)It is turned off by hydrolysis of its bound GTP to GMP.

Question

Quizplus · Accepted Answer

Ras activity is turned off by hydrolysis of its bound GTP to GDP. This is because Ras is a GTPase enzyme and can catalyze the hydrolysis of GTP to GDP. When Ras is bound to GTP, it is active and can transmit signals downstream. However, when GTP is hydrolyzed to GDP, Ras becomes inactive and cannot continue transmitting signals. Therefore, this is the mechanism by which Ras activity is turned off.

How Is Ras Activity Turned Off