Cathepsin G is an enzymatic protein belonging to the peptidase or protease families. In humans, it is coded by the CTSG gene. This enzyme degrades collagen and proteoglycan and can also cause the release of angiotensin II from angiotensin I or angiotensinogen. It has been implicated in connective tissue diseases such as emphysema and rheumatoid arthritis. Description: Human neutrophils.