Burnell J N, Roy A B
Biochim Biophys Acta. 1978 Nov 10;527(1):239-48. doi: 10.1016/0005-2744(78)90273-5.
ATP sulphurylase (ATP:sulphate adenylyltransferase, EC 2.7.7.4) as been purified about 2500-fold from rat liver. It was free of ATPase, inorganic pyrophosphatase, adenosine phosphosulphate kinase and ADP sulphurylase activities. The enzyme was homogeneous to chromatography on Sepharose 4B and to density-gradient sedimentation; it was not homogeneous to acrylamide gel electrophoresis nor to sedimentation in the ultracentrifuge. Possible reasons for this heterogeneity are considered. The molecular weight of the enzyme is 410 000 as measured by chromatography on Sepharose 4B. The v is 0.80, suggesting that ATP sulphurylase is a lipoprotein. The enzyme activity is associated with a pigment having a lambdamax of 410 nm. Studies of the forward, reverse and ATP-PPi exchange reactions catalysed by ATP sulphurylase have shown that these are sequential bi-bi reactions, with ATP being the first substrate bound and adenosine phosphosulphate the last product released. The results are incompatible with previous suggestions that the ATP sulphurylase of rat liver catalysed a bi-bi ping-pong reaction.
已从大鼠肝脏中纯化出约2500倍的ATP硫酸化酶（ATP：硫酸腺苷酰转移酶，EC 2.7.7.4）。它不含ATP酶、无机焦磷酸酶、腺苷磷酸硫酸激酶和ADP硫酸化酶活性。该酶在琼脂糖4B柱上进行层析以及在密度梯度离心中沉降时表现均一；但在丙烯酰胺凝胶电泳以及超速离心中沉降时不均一。文中考虑了造成这种不均一性的可能原因。通过琼脂糖4B柱层析测定，该酶的分子量为410000。其v值为0.80，表明ATP硫酸化酶是一种脂蛋白。该酶活性与一种最大吸收波长为410nm的色素有关。对ATP硫酸化酶催化的正向、反向和ATP-PPi交换反应的研究表明，这些都是有序的双底物双产物反应，其中ATP是第一个结合的底物，腺苷磷酸硫酸是最后一个释放的产物。这些结果与之前关于大鼠肝脏ATP硫酸化酶催化双底物乒乓反应的观点不一致。
