多头绒泡菌PSCL32.5蛋白的性质及其含量在细胞周期中的变化

用免疫印迹技术检测到低等真核生物多头绒泡菌中含有两种与HeLa细胞SC35单克隆抗体反应的蛋白，其分子量分别为32．5kD和82．5kD，将其命名为PSCL32．5和PSCL82．5。用SDS—PAGE技术对PSCL32．5蛋白进行了纯化，用等电聚焦方法确定PSCL32．5蛋白的等电点为6．19。应用免疫印迹技术检测多头绒泡菌细胞周期不同时相的PSCL32．5含量，发现该蛋白的含量在细胞周期中是变化的，在S早期时含量最低，从S期到G2期含量逐步增高，G2期后期含量最高。

The Characteristics of PSCL32.5 Protein from Physarum polycephalum and the Variation of the Content Through Cell Cycle

Crude fraction of Arg/Ser-rich proteins (SR proteins) were isolated from plasmodia of Physarum polycephalum and immunoassayed by western blot with a monoclonal antibody against SC35 protein from HeLa cell.Two polypeptides were detected by the antibody,suggesting that they were SCL(SC35-like) proteins.The SCL proteins have their mass weight of 32.5 kD and 82.5 kD,respectively,and so were termed PSCL32.5 and PSCL82.5 in this paper.The PI of PSCL32.5 was ascertained as 6.19 by IEF after a further purification of the protein with SDS-PAGE.The densitometric scanning of the western blot bands of PSCL32.5 isolated at different phases of cell cycle of P.polycephalum demonstrated that the relative content of the protein varied through the cell cycle:it appeared as the lowest at early S phase,showed increases from S phase to G_2 phase,and peaked at late G_2 phase.