Description
HTRF heparan sulfate substrate labeled with both biotin and Eu3+ Cryptate used with HTRF SA-XL665, allows to monitor heparanase activity with the robustness of HTRF technology.
Heparanase is an enzyme that cleaves heparan sulfate, and thereby releases growth factors that are implicated in tumor cell proliferation, metastasis and angiogenesis.
HTRF assays offer many advantages over other technologies:
Homogeneous add-and-read format
No wash steps
Low background
Straightforward miniaturization from 96- or 384-well microplates to high density assay formats such as 384-well low volume and 1536-well plates
Stable signal, providing flexibility in time of readout or size of assays
Assay principle
The HTRF heparanase assay is based on our proprietary heparan sulfate substrate, labeled with both biotin and Eu3+ Cryptate. Active heparanase enzyme cleaves the substrate causing the loss of energy transfer, and thus a reduction in SA-XL665 emissions.
Assay protocol
The assay is run as a two-step process: 1.Heparanase enzymatic reaction: Mix together, the substrate, the heparanase and/or compounds, incubate for 30 min at 37°C (We recommend a time course study to determine the optimal stimulation time) 2.Heparanase activity detection: Add Streptavidin-XL665.
Heparanase assay: enzymatic kinetic
HTRF Heparanase assay was performed using a range of enzyme concentrations. The heparanase enzyme reaction was allowed to proceed for various times prior to adding SA-XL665 and the emissions detected. The effects of heparanase enzyme concentration and the enzyme reaction time on substrate degradation are shown here. Based on the linearity of the enzyme dose-response, enzyme consumption and incubation time results, 90 ng/mL of heparanase incubated for 30 minutes at 37ºC was chosen for inhibitor screening.
Heparanase assay: inhibitory effect of suramin
Heparanase assay was performed using a range of enzyme concentrations with a final assay volume of 20 µL. Then an inhition assay was performed using heparanase at 90ng/mL incubated for 30 minutes at RT in presence of various concentrations of Suramin.
Fig A shows the Heparanase assay standard curve, assay CVs were lower than 3%. Fig.B shows the inhibitory effect of Suramin, a known inhibitor of heparanases. The IC50 was calculated at 4 µM, which is in agreement with values calculated using radiometric methods (1-10µM).
