Cystatin S: a cysteine proteinase inhibitor of human saliva.
An acidic protein of human saliva, which we named SAP-1 previously, is now shown to be an inhibitor of several cysteine proteinases. The protein inhibited papain and ficin strongly, and stem bromelain and bovine cathepsin C partially. However, it did not inhibit either porcine cathepsin B or clostripain. The mode of the inhibition of papain was found to be non-competitive. The name cystatin S has been proposed for this salivary protein in view of the similarities in activity and structure to other cysteine proteinase inhibitors such as chicken egg-white cystatin and human cystatins A, B, and C. The cystatin S antigen was detected immunohistochemically in the serous cells of human parotid and submaxillary glands.
D055312:Cystatin A; D015891:Cystatins; D010450:Endopeptidases / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D007700:Kinetics; D011480:Protease Inhibitors / Q000494:pharmacology*; D011506:Proteins / Q000302:isolation & purification / Q000494:pharmacology*; D012463:Saliva / Q000032:analysis*; D055333:Salivary Cystatins; D012471:Salivary Proteins and Peptides / Q000494:pharmacology*
C525173:CST4 protein, human; D055312:Cystatin A; D015891:Cystatins; D011480:Protease Inhibitors; D011506:Proteins; D055333:Salivary Cystatins; D012471:Salivary Proteins and Peptides; C026407:CSTA protein, human; D010450:Endopeptidases