Sato K, Nakashima T, Shimizu S
J Nutr Sci Vitaminol (Tokyo). 1984 Oct;30(5):405-13. doi: 10.3177/jnsv.30.405.
A simple spectrophotometric method for assay of ATP: cob(I)alamin Co-beta-adenosyltransferase was established. By using this method, specific activity of the enzyme in Protaminobacter ruber was found to be the highest in the logarithmic growth phase. The enzyme was highly purified from the cells in that phase and characterized. The molecular weight of the enzyme was estimated as 44,000 by gel filtration. The optimal pH and temperature were about 8.0 and 50 degrees C, respectively. Among divalent metal ions tested, only Mg2+ was effective for the enzyme activity. Km values for ATP and hydroxocobalamin were 250 microM and 26.3 microM, respectively. Substrate analogs such as GTP and CTP had only small activity in the enzymatic reaction.
建立了一种用于测定ATP：钴胺素Co-β-腺苷转移酶的简单分光光度法。通过使用该方法，发现红原蛋白杆菌中该酶的比活性在对数生长期最高。在该阶段从细胞中高度纯化该酶并进行表征。通过凝胶过滤估计该酶的分子量为44,000。最佳pH和温度分别约为8.0和50℃。在所测试的二价金属离子中，只有Mg2+对酶活性有效。ATP和羟钴胺素的Km值分别为250μM和26.3μM。底物类似物如GTP和CTP在酶促反应中只有很小的活性。
