Age variation in histidinoalanine cross-links in proteoglycan subunits from human articular cartilage

The proteoglycan subunits isolated from human articular cartilage of various ages (ranging from the newborn to the mature adult) were analyzed for their content of histidinoalanine. It was noted that while the young juveniles and adolescents contained about 1 nmole of histidinoalanine per mg protein, the skeletally mature adults contained about twice this amount. Unlike many age-related changes in proteoglycan structure that occur prior to the end of growth, this variation would appear to be more related to maturation of the adult.