Latexin, also known as tissue carboxypeptidase inhibitor, is the only mammalian carboxypeptidase inhibitor identified so far. Latexin was initially identified as a marker of neurons in the lateral neocortex of the developing brain (hence Latexin) (1). Further studies have shown that Latexin is highly expressed in mast cells and macrophages (2, 3). It is induced in acute pancreatitis and lung inflammatory disease. In addition, it is able to inhibit carboxypeptidases from the pancreas (CPA1 and CPA2) and mast cells (CPA3) (4). Therefore, it is thought that Latexin primarily functions in inflammation and innate immunity pathways. Compared to other carboxypeptidase inhibitors from plants and parasites, the 222 amino acid Latexin is much larger and more importantly, it lacks some conserved C-terminal residues, which interact with the target carboxypeptidase in a substrate-like manner (5). This distinct feature of Latexin suggests that it has a different carboxypeptidase inhibition mechanism.
Recombinant Mouse Latexin Protein, CF
R&D Systems | Catalog # 3620-PI
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Key Product Details
- R&D Systems E. coli-derived Recombinant Mouse Latexin Protein (3620-PI)
- Quality control testing to verify active proteins with lot specific assays by in-house scientists
- All R&D Systems proteins are covered with a 100% guarantee
Source
E. coli
Accession Number
Applications
Inhibition Activity
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Product Specifications
Source
E. coli-derived mouse Latexin protein
Glu2-Glu222, with an N-terminal Met and 6-His tag
Accession # P70202
Glu2-Glu222, with an N-terminal Met and 6-His tag
Accession # P70202
Purity
>95%, by SDS-PAGE under reducing conditions and visualized by silver stain.
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
N-terminal Sequence Analysis
Met
Predicted Molecular Mass
26 kDa
SDS-PAGE
29 kDa, reducing conditions
Activity
Measured by its ability to inhibit carboxypeptidase A1 cleavage of the colorimetric peptide substrate Ac-Phe-Thiaphe-OH in the presence of 5,5’Dithio-bis (2-nitrobenzoic acid) (DTNB). Edwards, K.M. et al. (1999) J. Biol. Chem. 274:30468.
The IC50 value is <2.0 nM, as measured under the described conditions.
The IC50 value is <2.0 nM, as measured under the described conditions.
Formulation, Preparation, and Storage
3620-PI
| Formulation | Supplied as a 0.2 μm filtered solution in Tris, NaCl and Glycerol. |
| 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.
|
Background: Latexin
References
- Arimatsu, Y. et al. (1994) Neurosci. Res. 20:131.
- Uratani, Y. et al. (2000) Biochem. J. 346:817.
- Aagaard A. et al. (2005) Structure 13:309.
- Normant E. et al. (1995) Proc. Natl. Acad. Sci. USA 92:12225.
- Reverter D. et al. (2000) Nat. Struct. Biol. 7:322.
Alternate Names
ECI, LXN, TCI
Gene Symbol
LXN
UniProt
Additional Latexin Products
Product Documents for Recombinant Mouse Latexin Protein, CF
Certificate of Analysis
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Note: Certificate of Analysis not available for kit components.
Product Specific Notices for Recombinant Mouse Latexin Protein, CF
For research use only
Related Research Areas
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Protocols
View specific protocols for Recombinant Mouse Latexin Protein, CF (3620-PI):
Materials
- Assay Buffer: 50 mM Tris, 10 mM CaCl2, 150 mM NaCl, 0.05% (v/v) Brij-35, pH 7.5 (TCNB)
- Recombinant Mouse Latexin (rmLatexin) (Catalog # 3620-PI)
- Recombinant Mouse Carboxypeptidase A1/CPA1 (rmCPA1) (Catalog # 2765-ZN)
- Trypsin (Sigma, Catalog # T-1426)
- Substrate: Ac-Phe-Thiaphe-OH (Peptides International, Catalog # STP-3621-PI),10 mM stock in DMSO
- 5,5’-dithio-bis(2-nitrobenzoic acid) (DTNB) (Sigma, Catalog # D-8130) 10 mM stock in DMSO
- 96 well clear plate (Costar, Catalog # 92592)
- Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
- Dilute rmCPA1 to 100 µg/mL with 1.0 µg/mL Trypsin in Assay Buffer.
- Incubate at room temperature for 1 hour.
- Dilute activated rmCPA1 to 20 µg/mL in Assay Buffer.
- Prepare a curve of rmLatexin (MW: 26,297 Da) in Assay Buffer. Make the following serial dilutions: 2500, 1600, 800, 300, 200, 150, 100, 50, 25, and 12.5 nM.
- Mix equal volumes of the rmLatexin curve dilutions and the diluted rmCPA1. Include a control (in duplicate) containing Assay Buffer and the diluted rmCPA1.
- Incubate mixtures at 37 °C for 1 hour.
- After incubation, dilute the mixtures 50 fold in Assay Buffer.
- Dilute Substrate to 200 µM in Assay Buffer containing 200 µM DTNB.
- Load 50 µL of the diluted incubated mixtures to a plate, and start the reaction by adding 50 µL of 200 µM Substrate mixture.
- Read in kinetic mode for 5 minutes at an absorbance of 405 nm.
- Derive the 50% inhibition concentration (IC50) for rmLatexin by plotting RFU/min (or specific activity) vs. concentration with 4‑PL fitting.
- The specific activity for rmCPA1 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/mol |
| 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:
- rmCPA1: 0.010 µg
- rmLatexin curve: 12.5, 8, 4, 1.5, 1.0, 0.75, 0.5, 0.25, 0.125, and 0.0625 nM
- Substrate: 100 μM
- DTNB: 100 μM
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