Alkaptonuria is a genetic disease where the metabolic pathway for degradation of tyrosine and phenylalanine is disrupted. Homogentisic acid (HGA), an intermediate of the pathway, builds up in the bloodstream of the patients and is excreted via urine. Over several decades, the high level of HGA accumulates in the structural tissues of the body, especially joint cartilage, and form a dark pigment in a process known as ochronosis. Patients then experience severe pain in their daily lives and often require multiple joint replacements in their lifetime.
We are interested in the structural changes in collagen proteins caused by ochronosis. We would also like to elucidate the structure and mechanism of formation of the dark pigment, the identity of which is still unknown.