Spock3, also known as testican-3, is a nervous system-expressed heparan sulfate proteoglycan belonging to a subgroup of the BM-40/SPARC/osteonectin family, the role of which in brain development is unclear. It inhibits the processing of pro-matrix metalloproteinase 2(MMP-2) by MT1-MMP and MT3-MMP. It is mostly confined to the developmental stage of the brain. Recombinant mouse Spock3, fused to His-tag at C-terminus, was expressed in insect cell and purified by using conventional chromatography techniques.