Application

Apyrase is used to hydrolyze nucleoside triphosphates and diphosphates. For hydrolysis of organic di and triphosphates, the optimal pH is 6, and for inorganic substrates, the optimal pH is 5.1. Apyrase, from Sigma, has been used in inhibition studies of platelet-aggregation .

At least two isoenzymes are found in different varieties of S. tuberosum: one with a high ATPase/ADPase ratio (~10) and another with a low ratio (~1).Reaction: ATP → ADP+P_i → AMP+2P_i.

Biochem/physiol Actions

Apyrase is found in all eukaryotes and some prokaryotes. Apyrase, from potato, has a crucial role in regulating growth and development. Apyrase is involved in the inactivation of synaptic ATP as a neurotransmitter following nerve stimulation and in the inhibition of ADP induced platelet aggregation to prevent thrombosis . Divalent metal ions are required for activity and best activity is observed with calcium ion at 5 mM.

Other Notes

This grade has a low ATPase/ADPase ratio.

Packaging

Sold on the basis of ATPase units.

100, 200, 500, 1000, 2000 units in glass bottle

Physical form

Partially purified, lyophilized powder containing potassium succinate buffer salts.

Preparation Note

Derived from red potato

Unit Definition

One unit will liberate 1.0 µmole of inorganic phosphate from ATP or ADP per min at pH 6.5 at 30 °C.