ylococcal peptidase i          (?&lt;=[^E])E
thermolysin                         [^DE](?=[AFILMV])
thrombin                            ((?&lt;=G)R(?=G))|((?&lt;=[AFGILTVM][AFGILTVWA]P)R(?=[^DE][^DE]))
trypsin_full                        ([KR](?=[^P]))|((?&lt;=W)K(?=P))|((?&lt;=M)R(?=P))
trypsin_exception                   ((?&lt;=[CD])K(?=D))|((?&lt;=C)K(?=[HY]))|((?&lt;=C)R(?=K))|((?&lt;=R)R(?=[HR]))
non-specific                        ()
trypsin                             ([KR](?=[^P]))</code></pre>
</di