Hydroxylysine is an amino acid, C6H14N2O3. It is most widely known as a component of collagen. A standard amino acid with the R' group consisting of an amino terminated butyl hydrocarbon chain, with a hydroxyl group on the carbon atom before the amino group. See also lysine which lacks the hydroxyl group of hydrolysine.

Structure is: NH2 - CH2 - CHOH - CH2 - CH2 - C2H4NO2

Number of hydrogens vary due to carboxyl/amino groups and the acidity or alkilinity of their sorroundings

See http://herkules.oulu.fi/isbn9514267990/html/x319.html for more in depth information about the biological context of this amino acid.