Cystatin SN/CST1 Protein, Human (HEK293, His)

Cystatin SN (CST1) is a component of human saliva that is immunologically similar to cystatin S but exhibits distinct specificity due to sequence variation. Cystatin SN has an isoelectric point of 7.5 and is a potent inhibitor of papain and dipeptidyl peptidase I, superior to Cystatin S in these activities. Cystatin SN/CST1 Protein, Human (HEK293, His) is the recombinant human-derived Cystatin SN/CST1 protein, expressed by HEK293 , with C-6*His labeled tag. The total length of Cystatin SN/CST1 Protein, Human (HEK293, His) is 121 a.a., with molecular weight of ~17.0 kDa.

Cystatin SN (CST1), a component of human saliva, belongs to the cysteine proteinase inhibitor family, sharing immunological similarity with cystatin S. Despite this similarity, Cystatin SN exhibits distinct specificity due to amino acid sequence variations. With a pI of 7.5, Cystatin SN stands out as a potent inhibitor of papain and dipeptidyl peptidase I, outperforming cystatin S in these inhibitory activities. Notably, both Cystatin SN and cystatin S demonstrate equal proficiency in inhibiting ficin. This highlights the intricate variations in the inhibitory capabilities within the cystatin family present in saliva, emphasizing their potential roles in regulating specific proteolytic activities.

Measured in a cytotoxicity assay using A549 human non-small-cell lung carcinoma cells. The ED₅₀ this effect is 0.4193 ng/mL, corresponding to a specific activity is 2.3849×10⁶ units/mg.

Human

HEK293

C-His

P01037 (W21-S141)

1469  [NCBI]

WSPKEEDRIIPGGIYNADLNDEWVQRALHFAISEYNKATKDDYYRRPLRVLRARQQTVGGVNYFFDVEVGRTICTKSQPNLDTCAFHEQPELQKKQLCSFEIYEVPWENRRSLVKSRCQES

Approximately 17.0 kDa

Greater than 95% as determined by reducing SDS-PAGE

Lyophilized powder.

Lyophilized from a 0.2 μm filtered solution of 20 mM MES, 150 mM NaCl, pH 5.5 or 50 mM Tris-HCL, 300 mM NaCl, pH 7.4.

<1 EU/μg, determined by LAL method.

It is not recommended to reconstitute to a concentration less than 100 μg/mL in ddH₂O. For long term storage it is recommended to add a carrier protein (0.1% BSA, 5% HSA, 10% FBS or 5% Trehalose).

Stored at -20°C for 2 years. After reconstitution, it is stable at 4°C for 1 week or -20°C for longer (with carrier protein). It is recommended to freeze aliquots at -20°C or -80°C for extended storage.

Room temperature in continental US; may vary elsewhere.