You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Protein", "Chemical"].

Please return the output as a JSON object of the format: {"Chemical" : ["Dexamethasone", ...], "Protein" : ["BRCA-1", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

In Vitro Reconstitution of Complexes between proMatrix Metalloproteinase-9 and the Proteoglycans Serglycin and Versican.
Previously we have shown that a fraction of the matrix metalloproteinase-9 (MMP-9) synthesized by the macrophage cell line THP-1 was bound to a chondroitin sulphate proteoglycan (CSPG) core protein as a reduction sensitive heteromer. It was also shown that the hemopexin-like (PEX) domain and the fibronectin-like (FnII) module in the enzyme are involved in the heteromer formation. In the present work we show that reduction sensitive and SDS-stable heteromers can be reconstituted in vitro by mixing proMMP-9 with either serglycin, versican or CSPGs isolated from various monocytic cell lines. In addition, a strong but SDS-soluble proMMP-9·CSPG heteromer was formed. The two macromolecules in the SDS-stable reduction sensitive heteromers were not linked together by disulphide bonds. As for the heteromer isolated from THP-1 cells, the in vitro reconstituted SDS-stable and SDS-soluble heteromers had a weaker binding to gelatin than the proMMP-9 monomer. Furthermore, gelatin inhibited the in vitro reconstitution of the heteromers, showing that the FnII module is involved in the complex formation. TIMP-1 could not be detected in the formed proMMP-9·CSPG complexes. However, the presence of TIMP-1 inhibited the formation of the SDS-soluble heteromer, but not the SDS-stable reduction sensitive heteromer. This indicates that different regions in the PEX domain are involved the formation of these heteromers. This article is protected by copyright. All rights reserved.
{"Chemical": ["SDS", "disulphide"], "Protein": ["FnII module", "PEX domain", "chondroitin sulphate proteoglycan (CSPG) core protein", "proMMP-9", "hemopexin-like (PEX) domain", "TIMP-1", "CSPG", "MMP-9", "CSPGs", "matrix metalloproteinase-9", "proMatrix Metalloproteinase-9", "fibronectin-like (FnII) module"]}