Biochemistry 4th Edition by Reginald Garrett, Charles Grisham

Exercise 9

Describe the effects on cAMP and glycogen levels in cells exposed to cholera toxin
Cholera toxin is an enzyme that covalently modifies the G -subunit of G proteins. (Cholera toxin catalyzes the transfer of ADP-ribose from NAD + to an arginine residue in G , an ADP-ribosylation reaction.) Covalent modification of G inactivates GTPase activity. Predict the consequences of cholera toxin on cellular cAMP and glycogen levels.