Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 2003-06-01

Purification and characterization of perchloric acid soluble protein from rat lung.

M Matsumoto, H Kanouchi, K Suzuki, K Kaneki, Y Kawasaki, T Oka

Index: Comp. Biochem. Physiol. B Biochem. Mol. Biol. 135(2) , 255-62, (2003)

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Abstract

We isolated a perchloric acid soluble protein from the post-mitochondria supernatant fraction of the rat lung and designated it as RLu-PSP1. The protein is soluble in 5% perchloric acid and was purified by ammonium sulfate fractionation and CM-Sephadex chromatography. The amino acid sequence of RLu-PSP was identical with that of rat liver PSP (RL-PSP). RLu-PSP inhibited protein synthesis in a rabbit reticulocyte lysate system. It was expressed mainly in cytoplasm of bronchioles and alveolar epithelial cells of the lung from 60-day-old rats. In 15-day-old rat embryos, the epithelial-lining of the terminal buds of the respiratory tree was immunopositive. The expression of RLu-PSP increased from the embryonic 15th day to the postnatal 40th day. This is the first report on the presence of a PSP in rat lung and on its involvement in the regulation of cellular growth and differentiation.