Microbiology Mechanism of action of pertussis toxin is all except: A Act by ADP ribosylation of GI subunit B Increase in calcium C Act by decreasing GTP D B subunit having ADP ribosylating activity 💡 Explanation Mechanism of action of pertussis toxin is all except: ✓ Correct Answer: A. Act by ADP ribosylation of GI subunit