Libouga D G, Aguié-Béghin V, Douillard R
Laboratoire de Biochimie des Macromolécules Végétales, Institut National de la Recherche Agronomique, Reims, France.
Int J Biol Macromol. 1996 Dec;19(4):271-7. doi: 10.1016/s0141-8130(96)01137-3.
In order to understand the mechanism of thermal gelation of rubisco, its native and heat denatured states were characterized by absorbance, fluorescence and circular dichroïsm spectroscopies as well as by differential scanning calorimetry in the presence of various salts. It appears that during the denaturation process, divalent anions are released while divalent cations are fixed by the protein, while it is disorganized and while the environment of its aromatic chromophores becomes more hydrophilic. The pH transition of gelation is shifted 1-2 pH units higher than the transition of denaturation temperature which occurs near the isoelectric point of the native molecule. This shift probably corresponds to the breaking of saline bridges within the protein molecule. Finally, a large effect of divalent cations on the phase diagram indicates that a particular denatured state is attained when these cations are in the denaturation medium.
为了理解核酮糖-1,5-二磷酸羧化酶/加氧酶（rubisco）热凝胶化的机制，通过吸光度、荧光、圆二色光谱以及在各种盐存在下的差示扫描量热法对其天然态和热变性态进行了表征。在变性过程中，二价阴离子被释放，而二价阳离子被蛋白质固定，同时蛋白质结构变得无序，其芳香发色团的环境变得更亲水。凝胶化的pH转变比变性温度转变高1 - 2个pH单位，变性温度转变发生在天然分子的等电点附近。这种转变可能对应于蛋白质分子内盐桥的断裂。最后，二价阳离子对相图有很大影响，表明当这些阳离子存在于变性介质中时会达到一种特定的变性状态。
