Cathepsin G (EC 22.214.171.124, chymotrypsin-like proteinase, neutral proteinase) is an enzymatic protein belonging to the peptidase or protease families. In humans, it is coded by the CTSG gene.
The protein encoded by this gene, a member of the peptidase S1 protein family, is found in azurophil granules of neutrophilic polymorphonuclear leukocytes. The encoded protease has a specificity similar to that of chymotrypsin C, and may participate in the killing and digestion of engulfed pathogens, and in connective tissue remodeling at sites of inflammation. Transcript variants utilizing alternative polyadenylation signals exist for this gene.