【摘要】 从玉米胚中分离出一组理化性质相似的可为钙所沉淀的蛋白。该组蛋白可被3％的三氯乙酸和55％的硫酸铵可逆沉淀，具有较高的热稳定性，在93～94℃下5min不沉淀。该组钙沉淀蛋白可被等于或大于1mmol／L的CaCl2可逆地沉淀，但不被MgCl2或NaCl沉淀。该组蛋白在EGTA存在下可与phenyl－sepharose4B结合而被含Ca2+的缓冲液所洗脱。它们由7种蛋白质组成，亚基分子量为16～103kD。它们的一些理化性质类似于从动物肌肉细胞中提取的钙结合蛋白calsequestrin，其功能可能与缓冲和调节细胞游离Ca2+水平有关。更多还原

【Abstract】 This paper reports a group of calcium-precipitable proteins (CaPPs) isolated from maize germ for the first timeby a procedure involving reversible precipitation by 3% trichloroacetic acidand 55% (NH4 )2SO4, heat denaturation and Ca2+-induced reversible precipitation. This group of CaPPs showedhigher heat stability, and kept undenaturated at 93-94℃ for 5 min. In addition, they could be reversibly precipitated when the Ca2+ concentration ofthe solution was equal to or higher than1 mmol/L (Fig. 1), bind hydrophobically to phenyl-sepharose 4B in the absence of Ca2+ and were dissociated fromphenyl-sepharose column in a Ca2-dependent manner (Fig. 2 ). Electrophoretic analysis showed that thisgroup of CaPPs consists of 7 proteins(Fig. 3 ), the molecular weights ofwhich subunits range from 16 to 103kD (Fig. 4 ). This group of CaPPsshowed some of the properties similar tocalsequestrin isolated from muscle cells,suggesting that they might be involvedin the regulation of intracellular Ca2-level through its buffering action.更多还原