Pepsin, was, in the 18th century, the first enzyme
to be discovered and the second enzyme to be crystalize
d. It is an enzyme created by the stomach
expressely for breaking down proteins
. Now, the problem arises as to how to create an enzyme for breaking down proteins without destroying the cell
that creates it, which is largely protein based. Pepsin is created with an extra 44 amino-acids bonded
to its active site
, in a form called pepsinogen
. Once pepsinogen is escorted out of the cell and into the highly acidic digestive fluids
acid cuts off the extra 44 amino-acids, thereby activating pepsin to do its duty of breaking apart proteins.
Molecular Weight: 35,000+ AMU
pH optimum: 1 - 4
Stability: Pepsin is stable up to a temperature of 60 degrees Celsius, and is irretrivably deactivated at a pH of 6
Pepsin types: A,B,C,D, With A being a supermajority.
Pepsin will not cleave at places bonded by valine, alanine or glycine.