Studies on ochronosis. II. Studies on benzoquinoneacetic acid, a probable intermediate in the connective tissue pigmentation of alcaptonuria

Benzoquinoneacetic acid, the quinone of homogentisic acid, given intraperitoneally to guinea pigs is distributed mainly into skin and cartilage, as found previously with homogentisic acid. In contrast to homogentisic acid, benzoquinoneacetic acid reacts chemically with proteins and homogenates of skin and cartilage in vitro to give products which may be similar to those formed during the development of ochronotic pigmentation of the connective tissues in alcaptonuria. The physical and chemical events leading to ochronosis are discussed.