Definition

1. Noun:
   • A salt or ester of pyrophosphoric acid: A chemical compound containing the pyrophosphate ion (P₂O₇⁴⁻), which consists of two phosphate groups linked together. It is involved in various biochemical energy transfer processes.

Examples of Usage

• Noun:
  • Adenosine triphosphate (ATP) is hydrolyzed to adenosine monophosphate and pyrophosphate.
  • The enzyme catalyzes the release of pyrophosphate from the nucleotide substrate.
  • Calcium pyrophosphate crystals can deposit in joints, causing inflammation.

Advanced Usage

• "Inorganic pyrophosphate (PPi)": This specific term refers to the free ion (P₂O₇⁴⁻) in biological systems, often a byproduct of biosynthetic reactions like DNA and protein synthesis.
  • Inorganic pyrophosphate is hydrolyzed by pyrophosphatase to orthophosphate, driving reactions forward.

Variants and Related Words

• Pyrophosphoric acid (n): The parent acid (H₄P₂O₇) from which pyrophosphate salts and esters are derived.
• Pyrophosphatase (n): An enzyme that catalyzes the hydrolysis of pyrophosphate into two phosphate ions.
• Diphosphate (n): A synonym often used interchangeably with pyrophosphate in biochemical contexts, especially for organic esters (e.g., adenosine diphosphate, ADP).

Synonyms

• Diphosphate: (In biochemistry, particularly for esters) A compound containing two phosphate groups.
• PPi: A common abbreviation for inorganic pyrophosphate.

Related Phrases

• Pyrophosphate bond: Refers to the high-energy phosphoanhydride bond linking the two phosphate groups in the pyrophosphate molecule.
  • The hydrolysis of the pyrophosphate bond releases significant energy.

Noun

1. a salt or ester of pyrophosphoric acid