Smythe E, Williams D C
Department of Biochemistry, Trinity College, Dublin, Ireland.
Biochem J. 1988 Jul 1;253(1):275-9. doi: 10.1042/bj2530275.
Uroporphyrinogen III synthase purified from rat liver is a monomer of Mr 36,000 by gel filtration and 28,000 by SDS/polyacrylamide-gel electrophoresis. The enzyme exists in two interconvertible forms separable on h.p.l.c. Both forms of the enzyme could be renatured with full activity after SDS/polyacrylamide-gel electrophoresis, demonstrating the absence of a reversibly bound cofactor. The enzyme activity could be inhibited by pyridoxal 5'-phosphate in the absence and in the presence of NaBH4, consistent with (an) essential lysine residue(s). The enzyme thus shows great similarity to that from Euglena gracilis.
从大鼠肝脏中纯化出的尿卟啉原III合酶，通过凝胶过滤法测得其分子量为36,000，呈单体形式，而通过SDS/聚丙烯酰胺凝胶电泳测得分子量为28,000。该酶以两种可相互转化的形式存在，可通过高效液相色谱法分离。在SDS/聚丙烯酰胺凝胶电泳后，两种形式的酶都能复性并具有完全活性，这表明不存在可逆结合的辅因子。在有无硼氢化钠存在的情况下，该酶的活性均可被5'-磷酸吡哆醛抑制，这与一个或多个必需的赖氨酸残基相符。因此，该酶与纤细裸藻中的酶具有很大的相似性。
