CST1
Function
Human saliva appears to contain several cysteine proteinase inhibitors that are immunologically related to cystatin S but that differ in their specificity due to amino acid sequence differences. Cystatin SN, with a pI of 7.5, is a much better inhibitor of papain and dipeptidyl peptidase I than is cystatin S, although both inhibit ficin equally well.
Sequence Similarities
Belongs to the cystatin family.
Tissue Specificity
Expressed in submandibular and sublingual saliva but not in parotid saliva (at protein level). Expressed in saliva, tears, urine and seminal fluid.
Cellular localization
- Secreted
Alternative names
Cystatin-SN, Cystain-SA-I, Cystatin-1, Salivary cystatin-SA-1, CST1