Apyrase from potatoes

Apyrase, also known as ATP-diphosphohydrolase, is expressed in wide variety of plant and animal tissues. The commercially accessible apyrase enzyme is isolated from potato tubers.

Apyrase from potatoes has been used:

• to deplete ATP
• to degrade endogenous extracellular ATP
• as a supplement in acid citrate dextrose solution to treat blood obtained from anesthetized mice

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.

Apyrase hydrolyses the phosphoanhydride bonds of nucleoside tri- and di-phosphates in the presence of divalent cations. It has wide substrate specificity for nucleotides. This property of the enzyme makes it suitable for different biotechnical applications, including DNA sequencing and platelet-aggregation inhibition. Apyrase has adenosine 5′-triphosphatase (ATPase) and adenosine 5′-diphosphatase (ADPase) activities.

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.

Sold on the basis of ATPase units.

Partially purified, lyophilized powder containing potassium succinate buffer salts.

Derived from white potato

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

This grade has an exceptionally high ATPase/ADPase ratio.