多管藻R-藻红蛋白和R-藻蓝蛋白的制备及其相对分子质量的测定

Preparation of R-phycoerythrin and R-phycocyanin from Polysiphonia urceolata and Determination of Their Relative Molecular Weight

以海生大型红藻多管藻(Polysiphonia urceolata)为材料,通过凝胶过滤层析、离子交换柱层析、凝胶电泳,得到纯度较高的R-藻红蛋白和R-藻蓝蛋白.在SDS-PAGE中,藻红蛋白表现出4个带有发色团的亚基α、β、β'、γ和γ',其相对分子质量分别为1.73×1041,.95×104,3.33×104和3.10×104;藻蓝蛋白则表现出3个带有发色团的亚基,分别是:α、β和β',其相对分子质量为1.75×1042,.13×104和2.62×104.不同相对分子质量的γ亚基和β亚基的发现都有别于先前的报道,这对藻红蛋白和藻蓝蛋白结构的研究提供了有价值的研究结果.选用Superdex-200凝胶柱层析对纯化的藻红蛋白和藻蓝蛋白进行了相对分子质量测定,藻红蛋白相对分子质量为2.4×105,藻蓝蛋白相对分子质量为1.36×105这表明纯化制备的藻红蛋白和藻蓝蛋白分别以六聚体((αβ)3γ(αβ)3)和三聚体((αβ)3)形式存在.

The R-phycocerythrin and R-phycocyanin in high purity are prepared from the marine red macroalga Polysiphonia urceolata by using gel filtration,ion-exchange chromatography,and gel electrophoresis.In SDS-PAGE,the purified R-phycocerythrin shows four chromophore-carrying subunits,α、β、γ and γ＇,of which mo-lecular weight are 1.73 × 1041,.95 × 104,3.33 × 104 and 3.10 × 104,respectively.The purified R-phyco-cyanin shows three chromophore-carrying subunits,α、β and β＇,of which molecular weight are 1.75 × 1042,.13 × 104 and 2.26 × 104r,espectively.The observation of the two different γ subunits from the prepared R-phycoerythrin and the two β subunits from the prepared R-PC is not consistent with the former reports.The relative molecular weight of the R-phycoerythrin and R-phycocyanin are determined to be 2.4 × 105 and 1.36 × 105 by employing the gel filtration on superdex-200.These results demonstrate that the prepared R-phycoery-thrin and R-phycocyanin exist respectively in forms of hexamer（（αβ） 3γ（αβ） 3） and trimer（（αβ） 3）.