Hydroxylysine (Hyl) 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 ...

with the molecular formula C₆H₁₄N₂O₃. It was first discovered in 1921 by

Donald Van Slyke Donald Dexter Van Slyke (March 29, 1883 – May 4, 1971) was a Dutch American biochemist. His achievements included the publication of 317 journal articles and 5 books, as well as numerous awards, among them the National Medal of Science and t ...

as the 5-hydroxylysine form. It arises from a post-translational hydroxy modification of

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −C ...

. It is most widely known as a component of

collagen Collagen () is the main structural protein in the extracellular matrix found in the body's various connective tissues. As the main component of connective tissue, it is the most abundant protein in mammals, making up from 25% to 35% of the whole ...

. It is biosynthesized from lysine via oxidation by

lysyl hydroxylase Lysyl hydroxylases (or procollagen-lysine 5-dioxygenases) are alpha-ketoglutarate-dependent hydroxylases enzymes that catalyze the hydroxylation of lysine to hydroxylysine. Lysyl hydroxylases require iron and vitamin C as cofactors for their ...

enzymes. The most common form is the (5''R'') stereoisomer found in collagen. However, the enzyme JMJD6 has recently been shown to be a lysyl hydroxylase which modifies an RNA splicing factor producing the (5''S'') stereoisomer. Additionally, in ''E. coli'', there has been at least one lysine ''N''-hydroxylase enzyme identified, named IucD.

References

External links

* {{MeshName, Hydroxylysine Amino acids