Löffler F, Müller R, Lingens F
Technische Universität Hamburg-Harburg, Arbeitsbereich Biotechnologie II, Germany.
Biochem Biophys Res Commun. 1991 May 15;176(3):1106-11. doi: 10.1016/0006-291x(91)90398-q.
Pseudomonas sp. CBS3 was grown with 4-chlorobenzoate as sole source of carbon and energy. Freshly prepared cell-free extracts converted 4-chlorobenzoate to 4-hydroxybenzoate. After storage for 16 hours at 25 degrees C only about 50% of the initial activity was left. Treatment at 55 degrees C for 10 minutes, dialysis or desalting of the extracts by gel filtration caused a total loss of the activity of the 4-chlorobenzoate dehalogenase. The activity could be restored by the addition of ATP, coenzyme A and Mg2+. If one of these cofactors was missing, no dehalogenating activity was detectable. The amount of 4-hydroxybenzoate formed was proportional to the amount of ATP available in the test system whereas CoA served as a real coenzyme. A novel ATP/coenzyme A dependent reaction mechanism for the dehalogenation of 4-chlorobenzoate by 4-chlorobenzoate dehalogenase from Pseudomonas sp. CBS3 is proposed.
假单胞菌属CBS3菌株以4-氯苯甲酸作为唯一碳源和能源进行培养。新鲜制备的无细胞提取物可将4-氯苯甲酸转化为4-羟基苯甲酸。在25℃下储存16小时后，仅剩下约50%的初始活性。提取物在55℃处理10分钟、透析或通过凝胶过滤进行脱盐，都会导致4-氯苯甲酸脱卤酶的活性完全丧失。通过添加ATP、辅酶A和Mg2+，活性可以恢复。如果缺少这些辅因子中的任何一种，就检测不到脱卤活性。形成的4-羟基苯甲酸的量与测试系统中可用的ATP量成正比，而辅酶A作为真正的辅酶。提出了一种由假单胞菌属CBS3菌株的4-氯苯甲酸脱卤酶催化4-氯苯甲酸脱卤的新的ATP/辅酶A依赖性反应机制。
