Study on proteoglycans having low-sulfated chondroitin 4-sulfate in human urine and serum

State analysis of low-sulfated chondroitin 4-sulfate (LSC) in human urine and serum was performed by the use of high performance liquid chromatography and Western blot analysis. It was revealed that the most amount of LSC in urine is present as urinary trypsin inhibitor and a small amount (about 10% of total LSC) is as an LSC chain. The LSC in serum is mainly present as a proteoglycan such as inter-alpha-trypsin inhibitor (ITI), with a molecular weight of 212 kDa, but a small amount of LSC-proteoglycans having molecular weights of 128 and 38 kDa were also observed on SDS-PAGE. Those two compounds may be fragments of ITI, or one of the compounds (128 kDa) may be pre-alpha-trypsin inhibitor which was found by Enghild et al. (J. Biol. Chem., 264, 15975 (1989)).