Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the metabolic breakdown of purine nucleotides. High blood concentrations of uric acid can lead to gout and are associated with other medical conditions including diabetes and the formation of ammonium acid urate kidney stones.
Uric acid is a diprotic acid with pKa1=5.4 and pKa2=10.3. Thus in strong alkali at high pH, it forms the dually charged full urate ion, but at biological pH or in the presence of carbonic acid or carbonate ions, it forms the singly charged hydrogen or acid urate ion, as its pKa1 is lower than the pKa1 of carbonic acid. As its second ionization is so weak, the full urate salts tend to hydrolyze back to hydrogen urate salts and free base at pH values around neutral. It is aromatic because of the purine functional group.
As a bicyclic, heterocyclic purine derivative, uric acid does not protonate as an oxygen [-OH] like carboxylic acids do. X-ray diffraction studies on the hydrogen urate ion in crystals of ammomium hydrogen urate, formed in vivo as gouty deposits, reveal the keto-oxygen in the 2 position of a tautomer of the purine structure exists as a hydroxyl group and the two flanking nitrogen atoms at the 1 and 3 positions share the ionic charge in the six-membered pi-resonance-stabilized ring.
Hold still
Don’t move I say
Wilt thou hear
My elegy
Head high
Preserve my pride
I shall defy the gallows
I and you and me
Well we just don’t know
What love can do
I pledge to you
That I won’t deceive
The heart that’s mine
As here I sit
I vow
Your history does not
Perish my love
The shame
Will be mine for a
Scarlet woman thou art
I and you and me
Well we just don’t know
What love can do
I pledge to you
That I won’t deceive
The heart that’s mine
Dead from the grave
We’re all slaves
To what we’ve got
Love
Is been through
The door