Cabrero C, Alemany S
Metabolismo, Nutrición y Hormonas, Fundación Jimenez Diaz, Madrid, Spain.
Biochim Biophys Acta. 1988 Feb 10;952(3):277-81. doi: 10.1016/0167-4838(88)90127-6.
Rat liver S-adenosyl-L-methionine synthetase exists in two forms which are, respectively, a dimer and a tetramer of an Mr 48,500 subunit. The high-molecular-mass form is converted into the low-molecular-mass form by incubation with 1.4 M LiBr. The kinetic properties of the low-molecular-mass form obtained by LiBr treatment are the same as those obtained with the low-molecular-mass S-adenosyl-L-methionine synthetase form purified from rat liver cytosol. These results demonstrate that the differences in specific activity and regulatory properties of the high-molecular-mass and the low-molecular-mass S-adenosyl-L-methionine synthetase forms are due to their different polymeric states.
大鼠肝脏S-腺苷-L-甲硫氨酸合成酶以两种形式存在，分别是由分子量为48,500的亚基组成的二聚体和四聚体。通过与1.4 M溴化锂孵育，高分子量形式可转化为低分子量形式。经溴化锂处理得到的低分子量形式的动力学性质，与从大鼠肝脏胞质溶胶中纯化得到的低分子量S-腺苷-L-甲硫氨酸合成酶形式相同。这些结果表明，高分子量和低分子量S-腺苷-L-甲硫氨酸合成酶形式在比活性和调节特性上的差异，是由于它们不同的聚合状态所致。
