Recombinant Human Hydroxyacid Oxidase-1/HAO-1 Protein, CF

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Recombinant Human Hydroxyacid Oxidase-1/HAO-1 Protein, CF Summary

Product Specifications

>95%, by SDS-PAGE under reducing conditions and visualized by Colloidal Coomassie® Blue stain at 5 μg per lane
Endotoxin Level
<1.0 EU per 1 μg of the protein by the LAL method.
Measured by its ability to oxidize glyoxylate. The specific activity is >200 pmol/min/μg, as measured under the described conditions.
E. coli-derived human Hydroxyacid Oxidase-1/HAO-1 protein
Leu2-Ile370, with an N-terminal Met and 6-His tag
Accession #
N-terminal Sequence
Predicted Molecular Mass
42 kDa
40 kDa, reducing conditions

Product Datasheets

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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 Supplied as a 0.2 μm filtered solution in Sodium Acetate, NaCl and Glycerol.
Shipping The product is shipped with dry ice or equivalent. 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, -70 °C as supplied.
  • 3 months, -70 °C under sterile conditions after opening.

Assay Procedure

  • Assay Buffer: 50 mM HEPES, pH 8.0 
  • Recombinant Human Hydroxyacid Oxidase‑1/HAO‑1 (rhHAO-1) (Catalog # 6197-GO)
  • 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: Sodium Glyoxylate (Sigma, Catalog # G4502), 400 mM stock in deionized water
  • Substrate Component 2: Amplex Ultra Red (AUR) (Molecular Probes, Catalog # A36006), 10 mM stock in DMSO
  • F16 Black Maxisorp Plate (Nunc, Catalog # 475515)
  • Fluorescent Plate Reader (Model: SpectraMax Gemini EM by Molecular Devices) or equivalent
  1. Dilute rhHAO-1 to 0.5 ng/µL in Assay Buffer.
  2. Prepare the Substrate Mixture, 4 mM Sodium Glyoxylate, 2 units/mL HRP and 100 µM AUR, in Assay Buffer.
  3. In a plate, load 50 µL of 0.5 ng/µL rhHAO-1, and start the reaction by adding 50 µL of the Substrate Mixture (step 2). Include a Substrate Blank containing 50 µL of the Assay Buffer and 50 µL of the Substrate Mixture.
  4. Read at excitation and emission wavelengths of 544 nm and 590 nm (top read), respectively in kinetic mode for 5 minutes. Note: A cutoff must be set manually at a wavelength of 570 nm.
  5. Calculate specific activity:

     Specific Activity (pmol/min/µg) =

Adjusted Vmax* (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, 2 mM Sodium Glyoxylate, and a curve of Hydrogen Peroxide (Sigma, Catalog # H1009) in Assay Buffer. Use this oxidized AUR curve to determine the conversion factor.

Per Well:
  • rhHAO-1: 0.025 µg
  • Sodium Glyoxylate: 2 mM
  • HRP: 1 unit/mL
  • AUR: 50 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: Hydroxyacid Oxidase-1/HAO-1

Glycolate oxidase is a member of the superfamily of the alpha ‑hydroxy acid oxidases (HAO), enzymes that are present in both plants and animals (1). It catalyzes the FMN-mediated oxidation of glycolate to glyoxylate and glyoxylate to oxalate with reduction of oxygen to hydrogen peroxide (2, 3). The co‑factor, FMN, is tightly bound but not covalently linked to the protein. In humans and other vertebrates, HAOs are found primarily in the peroxisomes of liver, kidney, and pancreas. Three HAOs have been identified in humans (4). HAO-1 is most highly expressed in liver and pancreas and is most active on two-carbon substrates such as glycolate. HAO-2 is expressed in liver and kidney and has greater activity against long-chain alpha ‑hydroxy acid substrates such as 2‑hydroxypalmitate. HAO-3 is expressed primarily in the pancreas. Recently, HAO has been identified as a major contributor to hyperoxaluria, a disorder in which large deposits of calcium oxalate form kidney stones (5).

  1. Caroline, V. et al. (2007) Arch. Biochem. Biophys. 465:410.
  2. Murray, M.S. et al. (2008) Biochemistry, 47:2439.
  3. Pennati, A. and G. Gadda. (2009) J. Biol. Chem. 284:31214.
  4. Jones, J.M. et al. (2000) J. Biol. Chem. 275:12590.
  5. Monico, G.C. et al. (2002) Kidney Int. 62:392.
Entrez Gene IDs
54363 (Human)
Alternate Names
(S)-2-hydroxy-acid oxidase; EC; Glycolate oxidase; GOX; GOX1MGC142227; GOXMGC142225; HAO1; HAO-1; HAOX1; hydroxyacid oxidase (glycolate oxidase) 1; hydroxyacid oxidase 1; Hydroxyacid Oxidase1; Hydroxyacid Oxidase-1

Product Specific Notices

Coomassie is a registered trademark of Imperial Chemical Industries Ltd.


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