Abstract
Immunohistochemical localizations of cytosolic and myofibrillar proteinases revealed a different myofiber locale for each enzyme in the rat. Although the cytosolic proteinase was most pronounced in mast cells within soleus and extensor digitorum longus (EDL) muscles, certain fibers of the EDL were also positive. The myofibrillar proteinase, on the other hand, appeared to be present in interstitial spaces between muscle fibers in the EDL but conversely present in some fibers of the soleus muscle.