Protein in the Nucleus Pulposus of the Intervertebral Disk

Abstract

THE nucleus pulposus of the normal human intervertebral disk consists of collagen fibrils dispersed in a gel of polysaccharide and protein complexes. During ageing collagen fibrils are deposited as a matrix showing increasing orientation with age as seen from X-ray diffraction investigations¹. In the case of specimens of more than 70 years of age, the normal photograph shows with the diagram of oriented collagen a clearly defined ring of spacing 4.7 Å., which is similar to that associated with a denatured β-protein¹ The presence of other components in the disk, for example, calcium phosphate, etc., will be discussed in a later publication. It was postulated from consideration of earlier work¹ that the soluble protein molecules normally found in a folded form in the nucleus had unfolded and formed a hydrogen-bonded lattice which gave rise to this spacing.