| Research Abstract |
Proteoglycan molecules generally consist of core protein (s), oligosacharide chains and glycosaminoglycan chains. The glycosaminoglycan components in the brain were extracted from the cerebral tissues of postnatal rats at 1, 10, 20, 30 days and 3-4 months of age. Two dimensional electrophoresis revealed that the content of chondroitin sulfate increased in early postnatal days, Chondroitin sulfate was the major component at 10 days of age and thereafter. Considerable amounts of chondroitin sulfate were soluble in a phosphate buffered saline. While the amount of heparan sulfate was very low. The extractability of heparan sulfate was below the detectable level. Based on these findings, it was concluded that the major glycosaminoglycan in the cerebral tissues was the soluble chondroitin sulfate during and after the development. Chondroitin sulfate proteoglycans soluble in phosphate buffered saline were purified from the cerebral tissues of postnatal rats. Six core proteins were obtained from purified fraction by digestion with protease-free chondroitinase ABC. Their molecular weights by SDS-PAGE were 250, 220, 150, 130, 105, and 93KDa. The composition of these core proteins changes during development. The 150kDa component was the major core protein in adulthood. Its content was very low in 1-day-old rats, but increased rapidly by 10 days of age. Considerable amounts of the 250kDa and 130kDa components were present in immature and adult brains. However, the 150kDa or 93kDa appeared after day 20. In contrast, the 220kDa core protein was predominant at 1 and 10 days of age, and it accounted for more than 60% of the total core proteins in 1-day-old rats. The amount of the 220kDa component markedly decreased and it was below the detectable level on day 30 and thereafter. These rnsults suggest that different kinds of soluble chondroitin sulfate proteoglycans are involved in development of the brain.
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