【项目简介】
Cystatin SA is a member of family 2 of the cystatin superfamily. Together with cystatins S and SN, it is produced by the salivary gland and secreted largely in the submandibular/sublingual saliva. Cystatin SA inhibits cathepsin L, but may not inhibit cathepsins B and H. The functions of Cystatin SA are largely unknown. However, it has been suggested to play a role in the control of periodontal tissue destruction.

【检验原理】
本试剂盒采用双抗体夹心ELISA法。酶标微孔板上预包被有抗人Cystatin SA抗体，当加入标准品和待测样本时，标准品和待测样本中的人Cystatin SA会和该抗体结合。洗板后，游离的其他成分被洗去，加入辣根过氧化物酶标记的的抗人Cystatin SA抗体可与被酶标板捕获的人Cystatin SA结合，形成“包被抗人Cystatin SA抗体+人Cystatin SA+抗人Cystatin SA抗体-HRP”免疫复合物。当加入TMB显色底物后，复合物上连接的HRP催化底物反应，生成蓝色产物，终止反应后变为黄色。在450nm处测定OD值，人Cystatin SA浓度与OD450值之间呈正比，可通过绘制标准曲线求出标本中人Cystatin SA的浓度。