研究方向
半胱氨酸蛋白酶抑制剂 SN (CST1) 是人类唾液的一种成分，属于半胱氨酸蛋白酶抑制剂家族，与半胱氨酸蛋白酶抑制剂 S 具有免疫学相似性。尽管存在这种相似性，半胱氨酸蛋白酶抑制剂 SN 由于氨基酸序列变化而表现出明显的特异性。Cystatin SN 的等电点为 7.5，是木瓜蛋白酶和二肽基肽酶 I 的有效抑制剂，其抑制活性优于 Cystatin S。值得注意的是，胱抑素 SN 和胱抑素 S 在抑制无花果蛋白酶方面表现出相同的能力。这凸显了唾液中半胱氨酸蛋白酶抑制剂家族抑制能力的复杂变化，强调了它们在调节特定蛋白水解活性中的潜在作用。
内毒素
< 0.1 EU/μg of the protein by LAL method.
制剂
Lyophilized from a 0.22 μm filtered solution of PBS, pH 7.4.Contact us for customized product form or formulation.
描述
Recombinant Human Cystatin-SN/CST1 Protein is produced by HEK293 cells expression system. The target protein is expressed with sequence (Trp21-Ser141) of human Cystatin SN/CST1 (Accession #NP_001889.2) fused with a 6×His tag at the C-terminus.
储存
Store at -20℃.Store the lyophilized protein at -20℃ to -80 ℃ up to 1 year from the date of receipt.
After reconstitution, the protein solution is stable at -20℃ for 3 months, at 2-8℃ for up to 1 week.未开盖的干粉蛋白在 -20°C至-80°C可保存12个月；
复溶之后，蛋白溶液在-20°C及以下可保存3个月，在2-8℃可保存1周。
生物活性
Measured by its ability to inhibit active Cathepsin L cleavage of a fluorogenic peptide substrate Z-LR-AMC. The IC50 value is <11.0 nM.
复溶
Centrifuge the vial before opening. Reconstitute to a concentration of 0.1-0.5 mg/mL in sterile distilled water. Avoid vortex or vigorously pipetting the protein. For long term storage, it is recommended to add a carrier protein or stablizer (e.g. 0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose), and aliquot the reconstituted protein solution to minimize free-thaw cycles.收到重组蛋白产品之后请检查蛋白冻干粉末是否贴于瓶底，如果粉末浮起，开盖之前请先低温离心。将蛋白用说明书中指定的缓冲液复溶至0.1-0.5 mg/mL（请注意蛋白复溶浓度不能低于0.1 mg/mL），室温平衡5-10 min保证充分溶解，复溶过程中请不要剧烈涡旋及吹打蛋白溶液。如需长期储存，建议复溶时添加载体蛋白或者稳定剂（如0.1% BSA, 5% HSA, 10% FBS 或者 5% 海藻糖），同时将复溶后的蛋白溶液按照需求进行分装，储存于-20°C至-80°C，随取随用，避免反复冻融。
背景信息
The cystatin superfamily encompasses proteins that contain multiple cystatin-like sequences. Some of the members are active cysteine protease inhibitors, while others have lost or perhaps never acquired this inhibitory activity. There are three inhibitory families in the superfamily, including the type 1 cystatins (stefins), type 2 cystatins and the kininogens. The type 2 cystatin proteins are a class of cysteine proteinase inhibitors found in a variety of human fluids and secretions, where they appear to provide protective functions. The cystatin locus on chromosome 20 contains the majority of the type 2 cystatin genes and pseudogenes. This gene is located in the cystatin locus and encodes a cysteine proteinase inhibitor found in saliva, tears, urine, and seminal fluid.
