Superacids are so strong that they can protonate such extremely weak bases as the alkanes, as was shown by Olah and independently by H. Hogeveen.    From Wordnik.com.  [Press Release: The 1994 Nobel Prize in Chemistry] Reference

Glu431 is conserved among GMPRs, suggesting that the Thr321 pathway has a crucial function in this reaction, perhaps operating in the reverse to protonate the ammonia leaving group.    From Wordnik.com.  [PLoS Biology: New Articles] Reference