海生红藻R-藻红蛋白和隐藻藻蓝蛋白光吸收系数测定

Absorption Coefficient Determination of R-Phycoerythrins and a Cryptomonad Phycocyanin from Marine Red Algae and Cryptomonad

选用Bradford法和Lowry法,以牛血清蛋白和γ-球蛋白作为标准蛋白,分别对从海生红藻异管藻(Heterosiphonia japonica)和多管藻(Polysiphonia urceolata)以及蓝隐藻(Chroomonas placoidea)中分离纯化的异管藻R-藻红蛋白(HR-PE)、多管藻R-藻红蛋白(PR-PE)、蓝隐藻藻蓝蛋白(Cr-PC)进行了蛋白浓度及其特征吸收峰的光吸收系数测定.根据2种方法和2种蛋白针对3种藻胆蛋白的测定结果以及影响结果的主要因素进行了细致地分析和比较,Lowry法是进行藻胆蛋白,尤其是六聚体藻红蛋白浓度及光吸收系数测定的更适合、准确的检测方法;在进行同类或相同藻胆蛋白之间相对含量、比例的定量分析时,Bradford法是一种更便捷的测定方法.由于藻胆蛋白光吸收系数值与选用的蛋白定量检测方法及其所用的标准蛋白直接相关,在使用和比较藻胆蛋白光吸收系数值时必须明确检测方法和标准蛋白,否则藻胆蛋白光吸收系数值将不具有可比性.

Two R-phycoerythrins, HR-PE and PR-PE, are isolated and purified from marine red alga Heterosiphonia japonica and Polysiphonia urceolata, respectively. And cryptomonad phycocyanin is prepared from marine cryptomonad Chroomonas placoidea. The protein concentration and light absorption coefficients of specific absorption maxima are determined using Bradford and Lowry methods with bovine serum albumin and γ-globulin are employed as standard proteins. Based on the comparison of the above mentioned methods and their influencing factors show that Lowry method is a more suitable and accurate method for absorption coefficient determination of phycobiliproteins, especially for hexameric phycoerythrins. For quantifing and comparising of the relative contents and the ratios of analogous or the same phycobiliproteins, Bradford method is more convenient one. Therefore, when absorption coefficient is to be used and to be compared with each other, the methods and standard proteins employed should be clarified because the absorption coefficients of phycobiliproteins are directly correlated to the methods and standards.