AN IMPROVED METHOD OF FIXATION FOR FORMALIN-SENSITIVE ENZYMES WITH SPECIAL REFERENCE TO MYOSIN ADENOSINE TRIPHOSPHATASE

Abstract

Studies have been made on the effect of fixatives containing substrate and other additives on the histochemical staining reaction for myosin adenosine triphosphatase activity in the leg muscle, and α-glycerophosphate and succinate dehydrogenase activities in the kidney of the rat. Myosin adenosine triphosphatase was well preserved in the presence of adenosine triphosphate in fixative prepared from methanol-free formaldehyde and buffered to pH 7.2 with cacodylate. Addition of sucrose was found to increase the enzyme preservation. Similar protection of the enzyme activity was afforded by other polyphosphates, particularly sodium pyrophosphate and, to less degree, thiamine pyrophosphate, adenosine diphosphate and uridine triphosphate. α-Glycerophosphate dehydrogenase was also preserved to greater degree by a similar fixative containing α-glycerophosphate than by substrate-free fixative. Succinate dehydrogenase was not significantly preserved in succinate-containing fixative. On the other hand, sucrose in the fixative increased the preservation of succinate dehydrogenase but had no appreciable effect on α-glycerophosphate dehydrogenase.