HISTOCHEMICAL DEMONSTRATION OF ACID TRIMETAPHOSPHATASE AND TETRAMETAPHOSPHATASE

Abstract

Trimetaphosphatase is an acid inorganic polyphosphatase whose distribution and properties differ from those of acid and alkaline organic phosphatases. It is the enzyme responsible for previously reported "acid" polyphosphatase" staining. The optimal staining solution for trimetaphosphtase by the Gomori method is: acetic acid 4.5 x 10^–2 M, lead acetate 4.6 x 10^–3 M, sodium trimetaphosphate 6 x 10^–4, M, adjusted to pH 4.8 with nitric acid. Best preservation of enzyme for staining is by post-fixation in the ribbon (dehydrate in cold acetone, embed in paraffin, section without wetting, spread ribbon on 0.02 M magnesium acetate pH 5.9, mount, drain and dry at 40-45°C). Brief standard fixation in cold neutral formaldehyde can also be used. Alcohol inactivates the enzyme. The report compares direct fixation to fixation in the anhydrous block, in the paraffin ribbon, and in the frozen section, and presents the effects of fifteen fixatives. Artifact staining in the Gomori method is shown to be accentuated or suppressed by choice of fixative.