They give a characteristic pale red precipitate with sodium pyrophosphate, soluble in an excess of the precipitant; they also form precipitates on the addition of platinic chloride and potassium ferrocyanide.
Also, the crystals can cause occasional attacks of very painful swelling (pseudogout, or acute pyrophosphate arthritis).
Many, but not all, people with osteoarthritis have calcium pyrophosphate crystals in their osteoarthritic joint cartilage.
A hypothetical, but typical, example involving pyrophosphate: enzyme 1: A + ATP « B + AMP + PP i...
This involves the prosthetic group thiamine pyrophosphate, or TPP.
How would you define pyrophosphate? Add your definition here.