Miyamoto T, Matsuno K, Imamura M, Kim S I, Honjoh K, Hatano S
Department of Food Science and Technology, Faculty of Agriculture, Kyushu University.
Microbiol Res. 1998 Apr;153(1):23-7. doi: 10.1016/s0944-5013(98)80017-7.
IMP dehydrogenase was purified from a crude extract of B, cereus cells. The molecular mass of the purified enzyme was estimated to be 56 kDa by SDS-PAGE and 225 kDa by gel filtration. The optimum pH of the enzyme was about 9.5. The first seven residues at N-terminus of the enzyme was determined to be Met-Trp-Glu-Ser-Lys-Phe-Val. The enzyme showed a significant specificity for inosine nucleotides among 15 purines and pyrimidines tested, but not acted on other purines and pyrimidines including inosine. Among 11 metal ions and 3 enzyme inhibitors tested, Al3+ activated the IMP dehydrogenase. The enzyme activity was strongly inhibited by Zn2+ and Fe3+.
IMP脱氢酶是从蜡样芽孢杆菌细胞的粗提取物中纯化得到的。通过SDS-PAGE估计纯化酶的分子量为56 kDa，通过凝胶过滤估计为225 kDa。该酶的最适pH约为9.5。酶N端的前七个残基被确定为Met-Trp-Glu-Ser-Lys-Phe-Val。在所测试的15种嘌呤和嘧啶中，该酶对肌苷核苷酸表现出显著的特异性，但对包括肌苷在内的其他嘌呤和嘧啶无作用。在所测试的11种金属离子和3种酶抑制剂中，Al3+激活了IMP脱氢酶。该酶的活性受到Zn2+和Fe3+的强烈抑制。
