Proteolytic Enzyme, Ready-to-Use, is intended for the proteolytic digestion of formalin-fixed, paraffin-embedded tissues, cell blocks or cell specimens prior to immunohistochemical (IHC) or in situ hybridization (ISH) procedures. Proteolytic digestion of formalin-fixed tissues improves accessibility of antibodies and DNA probes to target sites within tissues. In IHC, proteolytic digestion exposes certain epitopes which have been masked during fixation. In ISH procedures, accessibility of DNA sequences is enhanced allowing better probe penetration and hybridization.