Cathepsin G (CTSG) Human Native Protein

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. [provided by RefSeq]

Function: Serine protease with trypsin- and chymotrypsin-like specificity. Cleaves complement C3. Has antibacterial activity against the Gram-negative bacterium P.aeruginosa, antibacterial activity is inhibited by LPS from P.aeruginosa, Z-Gly-Leu-Phe-CH2Cl and phenylmethylsulfonyl fluoride. Ref.6 Ref.9 Ref.11

Catalytic activity: Specificity similar to chymotrypsin C.

Enzyme regulation: Inhibited by soybean trypsin inhibitor, benzamidine, the synthetic peptide R13K, Z-Gly-Leu-Phe-CH2Cl, phenylmethylsulfonyl fluoride, 3,4-dichloroisocoumarin, DFP, SBTI and alpha-1-antitrypsin. Inhibited by LPS from P.aeruginosa but not by LPS from S.minnesota. Not inhibited by elastinal, CMK, TLCK and ETDA. Ref.6 Ref.9 Ref.11

Subcellular location: Cell surface Ref.6.

Sequence similarities: Belongs to the peptidase S1 family.Contains 1 peptidase S1 domain.

Biophysicochemical propertiesKinetic parameters:KM=1.15 mM for Z-Lys-SBzl Ref.6KM=0.26 mM for Suc-Ala-Ala-Pro-Phe-SBzl