Hydroxyproline is a common nonproteinogenic amino acid. In mammals, hydroxyproline is found only in elastin and collagen. However, it exists in a variety of other proteins in plants. Hydroxyproline is formed by proline hydroxylase in the peptide chain as a post-translational modification and can not be formed from free proline. A variety of diseases such as neoplastic, renal or bone disease, inflammatory, endocrine and autoimmune disorders affect collagen turnover and cause elevated urine and serum hydroxyproline. Hydroxyproline hydrolysates in tissue can be used for the measurement of the amount of collagen or gelatin present.

The Hydroxyproline Colorimetric Assay Kit provides a sensitive, simple and convenient way for detection of hydroxyproline in tissue or protein/peptide hydrolysates based on colorimetric method. The assay can also be used for measurement of hydroxyproline content in other biological samples such as serum or urine with a prior purification process. The result can be easily qualified using a microtiter plate reader or a spectrophotometer at 560 nm. The assay is useful over the range of 0.1-2 μg.