Bacterial expression and functional reconstitution of human heparanase

Molecular model of human heparanase. •First bacterial expression system of human heparanase.•Individually expressed subdomains fold independently.•CD-derived secondary structure corresponds to secondary structure prediction.•Efficient screening systems for heparanase inhibitors. Human heparanase is a heparan sulfate degrading enzyme located in the extracellular matrix playing a decisive role in angiogenesis and tumor metastasis. Translated as a 65kDa inactive prae-form, the protein is processed into an 8kDa and a 50kDa subunit which form a non-covalently associated active heterodimer. We have expressed the two subunits separately in Escherichia coli which yielded active human heparanase upon reconstitution. The two purified subunits folded independently and secondary structure analysis by far-UV CD spectroscopy gave 33.1/11.1% α/β content for the 50kDa subunit and 6.9/49% α/β content for the 8kDa subunit. This heparanase expression system is easy and can be used for efficient screening for enzyme inhibitors.