Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF

Catalog # Availability Size / Price Qty
Product Details
Citations (3)
Supplemental Products

Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to inhibit Recombinant Human Complement Component C1s (Catalog # 2060-SE) cleavage of a colorimetric peptide substrate, N-carbobenzyloxy-Lys-ThioBenzyl ester (Z-K-SBzl). The IC50 is <2.6 nM, as measured under the described conditions.
Human plasma-derived Serpin G1/C1 Inhibitor protein
The human plasma used for the isolation of this product were certified by the supplier to be HIV-1 and HBsAg negative at the time of shipment. Human blood products should always be treated in accordance with universal handling precautions.
N-terminal Sequence
93 kDa, reducing conditions

Product Datasheets

You must select a language.



Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.


Formulation Lyophilized from a 0.2 μm filtered solution in Sodium Acetate and NaCl.
Reconstitution Reconstitute at 0.5 mg/mL in sterile, deionized water.
Shipping The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 6 months from date of receipt, -20 to -70 °C as supplied.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.

Assay Procedure

  • Assay Buffer: 50 mM Tris, 10 mM CaCl2, 0.15 M NaCl, and 0.05% Brij-35 (w/v), pH 7.5 (TCNB)
  • Human Serpin G1/C1 Inhibitor (hSerpin G1) (Catalog # 2488-PI)
  • Recombinant Human Complement Component C1s (rhC1s) (Catalog # 2060-SE)
  • Substrate Z-Lys-SBzl (Bachem, Catalog # M-1300), 10 mM in DMSO
  • 5,5’-Dithobis(2-Nitrobenzoic acid) (DTNB) (Sigma, Catalog # D-8130), 10 mM in DMSO
  • 96-well Clear Plate (Costar, Catalog # 92592)
  • Fluorescent Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
  1. Dilute rhC1s to 2 µg/mL in Assay Buffer.
  2. Prepare a curve of hSerpin G1 (MW: 93,000 Da) in Assay Buffer. Make the following serial dilutions: 2000, 1000, 500, 100, 50, 25, 12.5, 4, 0.8 and 0.2 nM.
  3. Combine 25 µL of diluted rhC1s and 25 µL of hSerpin G1 at each concentration of the curve. Include two rhC1s blanks containing Assay Buffer in place of hSerpin G1.
  4. Incubate mixtures at room temperature for 30 minutes.
  5. Dilute the mixtures 5-fold by combining 50 µL of reaction mixture with 200 µL Assay Buffer.
  6. Dilute substrate to 200 μM with Assay Buffer with 200 μM DTNB.
  7. Load into plate 50 µL of the diluted incubated mixtures, and start the reaction by adding 50 µL of 200 µM substrate/DTNB mixture.
  8. Read at an absorbance of 405 nm in kinetic mode for 5 minutes.
  9. Derive the 50% inhibition concentration (IC50) for hSerpin G1 by plotting OD/min (or specific activity) vs. concentration with 4-PL fitting.
  10. The specific activity for rhC1s at each point may be determined using the following formula (if needed):

     Specific Activity (pmol/min/µg) =

Adjusted Vmax* (OD/min) x well volume (L) x 1012 pmol/M
ext. coeff** (M-1cm-1) x path corr.*** (cm) x amount of enzyme (µg)

     *Adjusted for Substrate Blank
     **Using the extinction coefficient 13260 M-1cm-1
     ***Using the path correction 0.32 cm
     Note: the output of many spectrophotometers is in mOD Per Well:
  • rhC1s: 0.010 µg (1.33 nM)
  • hSerpin G1 curve: 100, 50, 25, 5, 2.5, 1.25, 0.625, 0.2, 0.04 and 0.01 nM
  • Substrate: 100 µM
  • DTNB: 100 µM
    • Reconstitution Calculator

      Reconstitution Calculator

      The reconstitution calculator allows you to quickly calculate the volume of a reagent to reconstitute your vial. Simply enter the mass of reagent and the target concentration and the calculator will determine the rest.


      Background: Serpin G1/C1 Inhibitor

      As a member of the serpin superfamily of serine protease inhibitors, Serpin G1/C1 inhibitor is the physiological inhibitor of activated C1r and C1s, two serine proteases involved in the classical complement pathway. In addition, it inhibits plasma kallikrein and coagulation factor XIIa, two serine proteases involved in the processing of kininogen to release bradykinin. Therefore, it plays an important role in regulating activation of both the complement and contact systems (1). Serpin G1 deficiency results in hereditary angioedema, which is characterized by recurrent episodes of localized angioedema of the skin, gastrointestinal mucosa or upper respiratory mucosa (2). The deduced amino acid sequence of human Serpin G1 precursor consists of 500 residues with a signal peptide. The mature protein of 478 amino acid residues is heavily glycosylated (1).

      1. Davis, A.E. III et al. (1993) Methods Enzymol. 223:97.
      2. Davis, A.E. III (2004) Drug News Perspect. 17:439.
      Entrez Gene IDs
      710 (Human)
      Alternate Names
      C1 Inhibitor; C1IN; C1INH; C1NH; HAE1; HAE2; Serpin G1; SERPING1 serpin peptidase inhibitor, clade G (C1 inhibitor), member 1

      Citations for Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF

      R&D Systems personnel manually curate a database that contains references using R&D Systems products. The data collected includes not only links to publications in PubMed, but also provides information about sample types, species, and experimental conditions.

      3 Citations: Showing 1 - 3
      Filter your results:

      Filter by:

      1. Glyco-engineered CHO cell lines producing alpha-1-antitrypsin and C1 esterase inhibitor with fully humanized N-glycosylation profiles
        Authors: T Amann, AH Hansen, S Kol, HG Hansen, J Arnsdorf, S Nallapared, B Voldborg, GM Lee, MR Andersen, HF Kildegaard
        Metab. Eng., 2018;0(0):.
        Species: Human
        Sample Types: Recombinant Protein
        Applications: Interferometry
      2. Extracellular Vesicle Proteins Associated with Systemic Vascular Events Correlate with Heart Failure: An Observational Study in a Dyspnoea Cohort.
        Authors: Zhang Y, Vernooij F, Ibrahim I, Ooi S, Gijsberts C, Schoneveld A, Sen K, den Ruijter H, Timmers L, Richards A, Jong C, Mazlan I, Wang J, Lam C, de Kleijn D
        PLoS ONE, 2016;11(1):e0148073.
        Species: Human
        Sample Types: Plasma
        Applications: ELISA Developmet
      3. Enzymatic properties of human kallikrein-related peptidase 12 (KLK12).
        Authors: Memari&lt;/LastName&gt;&lt;ForeNam N&lt;/Initial, Memari N, Jiang W, Diamandis EP, Luo LY
        Biol. Chem., 2007;388(4):427-35.
        Species: Human
        Sample Types: Recombinant Protein
        Applications: Enzyme Assay


      No product specific FAQs exist for this product, however you may

      View all Proteins and Enzyme FAQs

      Reviews for Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF

      There are currently no reviews for this product. Be the first to review Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF and earn rewards!

      Have you used Human Serpin G1/C1 Inhibitor (Plasma) Protein, CF?

      Submit a review and receive an Amazon gift card.

      $25/€18/£15/$25CAN/¥75 Yuan/¥1250 Yen for a review with an image

      $10/€7/£6/$10 CAD/¥70 Yuan/¥1110 Yen for a review without an image

      Submit a Review