Hawkinsin (also known as 2-cystenyl-1,4-dihydroxycyclohexenylacetate) is an

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

, which is formed after detoxification of a reactive tyrosine metabolite (quinol acetate) by glutathione. Hawkinsin is

ninhydrin Ninhydrin (2,2-dihydroxyindane-1,3-dione) is an organic compound with the formula C6H4(CO)2C(OH)2. It is used to detect ammonia and amines. Upon reaction with these amines, ninhydrin gets converted into deep blue or purple derivatives, which are ...

positive (a common test to detect

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

and

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

with a free -NH₂ group). It is found in elevated concentrations in the urine in

hawkinsinuria Hawkinsinuria is an autosomal dominant metabolic disorder affecting the metabolism of tyrosine. Normally, the breakdown of the amino acid tyrosine involves the conversion of 4-hydroxyphenylpyruvate to homogentisate by 4-hydroxyphenylpyruvate di ...

, which is probably related to the depletion of glutathione and resulting high excretion of 5-oxoproline.

References

Alpha-Amino acids Sulfur amino acids Thioethers Cyclohexenes Non-proteinogenic amino acids {{organic-compound-stub