Pavagi S, Kochhar S, Kochhar V K, Sane P V
National Botanical Research Institute, Lucknow, India.
Biochem Mol Biol Int. 1995 Jul;36(3):649-58.
Homoserine dehydrogenase (HSDH) has been purified to homogeneity from spinach leaves using ammonium sulphate fractionation followed by ion exchange chromatography, gel filtration and FPLC techniques. The purified enzyme has a relative molecular mass of 220,000 and subunit molecular mass of 55,000 and probably occurs as a tetramer. The enzyme was found to be sensitive to threonine and also exhibited aspartate kinase (AK) activity, which was also sensitive to threonine suggesting that it is a bifunctional protein. The enzyme protein also gave a positive cross reaction with antibodies raised against purified AK isoenzymes. Both HSDH and AK activities were stimulated by calcium and calmodulin.
已通过硫酸铵分级分离，随后进行离子交换色谱、凝胶过滤和快速蛋白质液相色谱（FPLC）技术，从菠菜叶中纯化出了同型丝氨酸脱氢酶（HSDH），使其达到了均一性。纯化后的酶相对分子质量为220,000，亚基分子质量为55,000，可能以四聚体形式存在。发现该酶对苏氨酸敏感，并且还表现出天冬氨酸激酶（AK）活性，该活性对苏氨酸也敏感，这表明它是一种双功能蛋白。该酶蛋白与针对纯化的AK同工酶产生的抗体也发生了阳性交叉反应。HSDH和AK活性均受到钙和钙调蛋白的刺激。
