Protein folding, unfolding and aggregation. Pressure induced intermediate states on the refolding pathway of horseradish peroxidase

We studied the refolding and aggregation of pressure unfolded proteins. Horseradish peroxidase was found to be very stable and no partially folded intermediates were populated during the refolding. However, the removal of the haem group or the Ca2+ ions or reduction of the disulfide bridge destabilized the protein, resulting in a significant amount of aggregation prone intermediate conformation. Substitution of the haem for fluorescent porphyrin however did not influence the refolding of the protein