Characterization of a large glycoprotein proteoglycan by size-exclusion chromatography combined with light and X-ray scattering methods

•Light and X-ray scattering methods combined with SEC are of complementarily useful.•A shark cartilage proteoglycan was first characterized using these methods.•The molecular weight (distribution) was estimated by SEC-LALLS.•The chain conformation (persistence length) was estimated by SEC-SAXS.

The molecular weight and chain conformation of a proteoglycan derived from shark cartilage in solution were characterized by size-exclusion chromatography combined with low-angle laser light scattering and small-angle X-ray scattering methods. The total molecular weight of the proteoglycan was 3.9 ± 0.2 million and the molecular weight of the main component was about 2.0 ± 0.2 million. The X-ray scattering data revealed that the main components of the proteoglycan are nearly equal to a chain with excluded volume and their persistence lengths range from 13.5 to 16.4 nm. These results show that size-exclusion chromatography combined with low-angle laser light scattering and small-angle X-ray scattering measurements are complementarily useful for characterization of large biopolymers in solution.