A Lexicographer From Nantucket

The Omnificent English Dictionary in Limerick Form has more than 3,000 definitions presented as limericks:

carboxypeptidase

In your mouth goes a protein intact,
Linked by peptide bonds, matter of fact!
N-type -ases undo
(From the N-side) the glue,
Yielding bits for your gut to extract.

And yet there’s no entry for dog.