Fitzgerald J W, Luschinski P C
Can J Microbiol. 1977 May;23(5):483-90. doi: 10.1139/m77-072.
Cell extracts of Pseudomonas C12B synthesized choline sulfate (COS) from SO42-, choline chloride, and ATP. However, most of the COS-forming activity was found in culture medium supernatants of this bacterium, and that which remained with the cells was cell wall-associated. Enzyme release was independent of the carbon and (or) sulfur source used for growth and was not suppressed by increasing the divalent cation concentration of the medium. The COS-synthesizing system was inhbited in vitro by L-cysteine (greater than or equal to 10(-3) mM), SO42- (greater than 0.1 mM), and choline chloride (greater than 0.1 M). L-Cysteine (0.1-5.0 mM) did not repress the synthesis of enzymes present in the system. COS formation from SO42- in vitro was increased 2.8-fold by 10 mM adenosine 5'-phosphosulfate (APS) and 5-fold by 1 mM 3'-phosphoadenosine,5'-phosphosulfate (PAPS) during a 4-h incubation period. APS (10 mM) also inhibited the incorporation of 35SO42- into COS. Culture supernatants incubated with Na235SO4 produced two 35S-labelled metabolites having electrophoretic mobilities similar to those exhibited by authentic APS and PAPS. The synthesis of these metabolites was also inhibited in vitro by unlabelled APS and by L-cysteine.
铜绿假单胞菌C12B的细胞提取物可利用硫酸根离子、氯化胆碱和三磷酸腺苷合成硫酸胆碱（COS）。然而，大部分COS形成活性存在于该细菌的培养基上清液中，而与细胞结合的部分则与细胞壁相关。酶的释放与用于生长的碳源和（或）硫源无关，且培养基中二价阳离子浓度的增加不会对其产生抑制作用。COS合成系统在体外受到L-半胱氨酸（大于或等于10^(-3) mM）、硫酸根离子（大于0.1 mM）和氯化胆碱（大于0.1 M）的抑制。L-半胱氨酸（0.1 - 5.0 mM）不会抑制系统中存在的酶的合成。在4小时的孵育期内，10 mM腺苷5'-磷酸硫酸酯（APS）可使体外由硫酸根离子形成COS的量增加2.8倍，1 mM 3'-磷酸腺苷5'-磷酸硫酸酯（PAPS）可使其增加5倍。APS（10 mM）也会抑制35SO42-掺入COS中。用Na235SO4孵育的培养上清液产生了两种35S标记的代谢产物，其电泳迁移率与 authentic APS和PAPS相似。未标记的APS和L-半胱氨酸在体外也会抑制这些代谢产物的合成。
