Recombinant Human Testican 2/SPOCK2 Protein, CF

Testican 2 encoded by the SPOCK2 gene is a proteoglycan highly expressed in brain (1, 2). The human and mouse cDNAs predict 94% identity between the deduced amino acid sequences from the two species, indicating a conserved function (3, 4). Testican 2 contains a Ca²⁺-binding domain and a C-terminal acidic domain with putative glycosaminoglycan attachment sites. In addition, it contains three potential inhibitory domains targeted toward three different classes of proteases, metallo, cysteine and serine proteases. However, these domains may not be involved directly in the inhibition of targeted proteases. For example, Testican 2 is not able to inhibit MMP-14 (MT1-MMP, a metalloprotease) activation of MMP-2 (5). The purified rhTestican 2 is not capable of inhibiting rhMMP-14 and rhCathepsin L (R&D Systems, Catalog # 918-MP and 952-CY) in assays using the fluorogenic peptide substrates (R&D Systems, Catalog # ES001 and ES008). Nevertheless, over expression of Testican 2 is able to abrogate inhibition of MMP-14 by other testican family members and to inhibit neurite outgrowth (6, 7).