apyrase activity

Definition

Target type: molecularfunction

Catalysis of the reaction: a ribonucleoside 5'-triphosphate + 2 H2O = a ribonucleoside 5'-phosphate + 2 phosphate. This reaction consists of two distinct successive phosphate-releasing steps, with NDPs as intermediates. Apyrases are active against both di- and triphosphate nucleotides (NDPs and NTPs) and hydrolyze NTPs to nucleotide monophosphates (NMPs). [EC:3.6.1.5]

Apyrase activity refers to the enzymatic hydrolysis of nucleoside triphosphates (NTPs), specifically ATP and ADP, into nucleoside monophosphates (NMPs) and inorganic phosphate (Pi). This catalytic process involves the sequential removal of two phosphate groups from the NTP molecule. Apyrases are commonly found in diverse organisms, including bacteria, plants, and animals, and they play crucial roles in a variety of cellular functions.

The molecular function of apyrase activity can be further categorized as follows:

**1. ATP hydrolysis:** Apyrases possess the ability to cleave the terminal phosphate group of ATP, generating ADP and Pi. This step is essential for energy metabolism and cellular signaling pathways.

**2. ADP hydrolysis:** Apyrases can further hydrolyze ADP into AMP and Pi. This process serves to regulate ADP levels, which are essential for maintaining cellular energy homeostasis.

**3. Regulation of cellular processes:** By controlling the levels of ATP and ADP, apyrases play a role in regulating various cellular processes, including:

* **Signal transduction:** Apyrases can modulate the activity of intracellular signaling pathways by influencing the levels of ATP and ADP, which act as second messengers.
* **Cell growth and differentiation:** Apyrases can influence cell proliferation and differentiation by regulating ATP and ADP levels.
* **Immune response:** Apyrases have been implicated in regulating immune responses by modulating the activity of immune cells.
* **Vascular function:** Apyrases can influence vascular tone and blood flow by controlling the levels of ATP and ADP, which are involved in vascular smooth muscle relaxation and contraction.

**4. Extracellular functions:** Apyrases are also found extracellularly, where they play a role in:

* **Platelet aggregation:** Apyrases can inhibit platelet aggregation by hydrolyzing ADP, which is a key mediator of platelet activation.
* **Inflammation:** Apyrases have been shown to inhibit inflammation by degrading pro-inflammatory mediators, such as ATP.

In summary, apyrase activity is a crucial enzymatic process involved in the hydrolysis of ATP and ADP, with profound implications for cellular energy metabolism, signal transduction, and a wide range of physiological functions.'
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Proteins (4)

Compounds (3)