Comparison of the Primary Structures of Acidic Proteinases and of Their Zymogens

Abstract
Proteinases with a pH-optimum of general proteolytic activity at pH below 6 are called acidic proteinases. Such enzymes were at first recognized as the proteinases of the vertebrate gastric juice, and for many years porcine pepsin and calf chymosin have been the most well-known members of this group.