Recombinant Human Lysosomal alpha-Glucosidase/GAA, CF Summary
Ala70-Cys952, with an N-terminal 6-His tag
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.
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 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.
- Assay Buffer: 0.1 M Sodium Acetate, pH 4.5
- Recombinant Human Lysosomal alpha -Glucosidase (rhGAA) (Catalog # 8329-GH)
- Stop Solution: 4.4 mM Dinitrosalicylic Acid, 1 M Potassium Tartrate, 0.4 M Sodium Hydroxide in deionized water
- Standard: Maltose (Sigma, Catalog # M5885), 20 mM stock in deionized water
- Substrate: Starch from potato (Sigma, Catalog # 85642), 2% (w/v) stock in deionized water
- 96-well Clear Plate (Catalog # DY990)
- Plate Reader (Model: SpectraMax Plus by Molecular Devices) or equivalent
- Dilute 20 mM Maltose standard by adding 200 µL of the 20 mM Maltose Standard to 600 µL of Assay Buffer for a 5 mM stock. This is the first point of the standard curve.
- Prepare the standard curve by performing five one-half serial dilutions of the 5 mM Maltose stock in Assay Buffer. Make sure there are 400 μL in each tube for each point of the curve (remove 400 μL from the last point of the curve). Prepare one tube with only 400 μL of Assay Buffer for the curve blank. The standard curve has a range of 19.5 to 625 nmol per well.
- Dilute rhGAA to 32 ng/μL in Assay Buffer.
- Dilute 2% starch to 1% in Assay Buffer by combining equal volumes of 2% starch and Assay Buffer.
- Prepare reactions by combining 20 μL of diluted rhGAA with 380 μL of 1% starch (step 4). Include a control by combining 20 μL of Assay Buffer with 380 μL of 1% starch.
- Vortex, spin, and then incubate reactions, control and standard curve at 37 °C for 1 hour.
- Add 400 uL of Stop Solution to all vials, including standard curve.
- Heat all vials at 95-100 °C for 6 minutes. Then, cool on ice. Tip: Use lid-locks on vials when heating.
- Load 250 µL of each dilution of the standard curve, reactions and controls to empty wells in triplicate in plate.
- Read plate at 546 nm (absorbance) in endpoint mode.
- Calculate specific activity:
Specific Activity (pmol/min/µg) =
|Adjusted glucose produced* (nmol) x (1000 pmol/nmol)|
|Incubation time (min) x amount of enzyme (µg)|
*Derived from the maltose standard curve using linear or 4-parameter fitting and adjusted for curve blank.Per Well:
- rhGAA: 0.200 µg
- Starch: 0.475%
Recombinant Human Lysosomal alpha-Glucosidase/GAA Protein, CF (Catalog # 8329-GH) hydrolyses both alpha-1,4- and alpha-1,6-glucosidic linkages on glycogen to release terminal glucose.
Recombinant Human Lysosomal alpha-Glucosidase/GAA Protein, CF (Catalog # 8329-GH) is measured by its ability to release glucose from starch.
2 μg/lane of Recombinant Human Lysosomal alpha-Glucosidase/GAA Protein (Catalog # 8329-GH) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 95-105 kDa.
Background: Lysosomal alpha-Glucosidase
Acid alpha-glucosidase (GAA) is an enzyme that is essential in the degradation of glycogen to glucose in the lysosome (1). Defects in GAA are the cause of glycogen storage disease II, also known as Pompe's disease, which is a rare autosomal recessive metabolic disorder that damages muscle and nerve cells throughout the body, primarily due to the accumulation of glycogen in the lysosome (2). Pompe disease occurs in babies, children, and adults who inherit a defective GAA gene and affects an estimated 5,000 to 10,000 people worldwide (3). Enzyme replacement therapy (ERT) is used to treat patients with this disease (4, 5).
- Hoefsloot L.H. et al. (1988) EMBO J. 7:1697.
- Wan, L. et al. (2008) J. Neurol. 255:831.
- Fukuda, T. et al. (2007) Curr. Neurol. Neurosci. Rep. 7:71.
- Van Gelder, C.M. et al. (2014) J Inherit Metab Dis. In press.
- Toscano, A. and Schoser, B. (2013) J. Neurol. 260:951.
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Reviews for Recombinant Human Lysosomal alpha-Glucosidase/GAA, CF
Average Rating: 5 (Based on 4 Reviews)
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Reason for Rating: The rhGAA was very comparable to native placental GAA for activity, uptake by cell lines and various inhibitors.