Recombinant Human QSOX1/Quiescin Q6 Protein, CF

Catalog #: 9209-QS Datasheet / COA / SDS

Catalog #	Availability	Size / Price	Qty
9209-QS-020

R&D Systems Recombinant Proteins and Enzymes

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All QSOX1/Quiescin Q6 Proteins and Enzymes

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Recombinant Human QSOX1/Quiescin Q6 Protein, CF Summary

Product Specifications

Purity

>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.

Activity

Measured by its ability to produce hydrogen peroxide during the oxidation of Dithiothreitol (DTT). The specific activity is >1,200 pmol/min/µg, as measured under the described conditions.

Source

E. coli-derived human QSOX1/Quiescin Q6 protein
Ser33-Ala546, with an N-terminal Met and 6-His tag

Accession #

O00391

N-terminal Sequence
Analysis

Met

Predicted Molecular Mass

58 kDa

SDS-PAGE

55 kDa, reducing conditions

Product Datasheets

9209-QS

Product Datasheet

COA

SDS

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.

9209-QS

Formulation	Supplied as a 0.2 μm filtered solution in Tris and NaCl.
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 opening.

Assay Procedure

Materials

Assay Buffer: 50 mM Sodium Phosphate, pH 7.5
Recombinant Human QSOX1/Quiescin Q6 (rhQSOX1) (Catalog # 9209-QS)
Coupling Enzyme: Horseradish Peroxidase (HRP) (250-330 U/mg) (Sigma, Catalog # P8375), 250 units/mL stock in 0.1 M Sodium Phosphate, pH 8.0
Substrate Component 1: Dithiothreitol (DTT) (Amresco, Catalog # 0281), 1 M stock in deionized water
Substrate Component 2: Amplex® Ultra Red (AUR) (Invitrogen, Catalog # A36006), 10 mM stock in DMSO
F15 Black Maxisorp Plate (Nunc, Catalog # 475515)
Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent

Dilute rhQSOX1 to 1 ng/μL in Assay Buffer.
Prepare a Substrate Mixture containing 100 µM AUR, 2 units/mL HRP, and 300 µM DTT in Assay Buffer. Make sure to add DTT to the Substrate Mixture right before loading the plate.
Load 50 μL of 1 ng/μL rhQSOX1 into the plate, and start the reaction by adding 50 μL of Substrate Mixture. Include a Substrate Blank containing 50 μL of Assay Buffer and 50 μL of Substrate Mixture.
Read at excitation and emission wavelengths of 544 nm and 590 nm in kinetic mode for 5 minutes. Note: A cutoff must be set at a wavelength of 570 nm.
Calculate specific activity:

Specific Activity (pmol/min/µg) =	Adjusted V_max* (RFU/min) x Conversion Factor** (pmol/RFU)
	amount of enzyme (µg)

*Adjusted for Substrate Blank
**Derived using a fluorescent standard prepared by incubating 50 µM AUR, 1 unit/mL HRP and 150 µM DTT and a curve of Hydrogen Peroxide (Sigma, Catalog # H1009) in Assay Buffer. Use this oxidized AUR curve to determine the conversion factor.

Per Well:

rhQSOX1: 0.05 μg
DTT: 150 µM
HRP: 1 unit/mL
AUR: 50 µM

Reconstitution Calculator

Background: QSOX1/Quiescin Q6

Sulfhydryl Oxidase-1 (QSOX1) is an approximately 80 kDa enzyme that contains thioredoxin and sulfhydryl oxidase domains (1-3). It is synthesized with a C-terminal transmembrane segment, but soluble secreted forms can be generated by alternative splicing or proteolytic shedding within the Golgi (4). Within the region encompassing both enzymatic domains and the central region, human QSOX1 shares 79% aa sequence identity with mouse and rat QSOX1. It plays a role nascent protein folding by mediating disulfide oxidation (4-6). This activity is required for Laminin incorporation into the extracellular matrix (7). QSOX1 is up-regulated in many cancers and supports tumor cell proliferation and invasion (1, 8).

References