1053-73-2Relevant articles and documents
Fluorometric coupled enzyme assay for N-sulfotransferase activity of N-deacetylase/N-sulfotransferase (NDST)
Atienza, Joshua,Tkachyova, Ilona,Tropak, Michael,Fan, Xiaolian,Schulze, Andreas
, p. 1093 - 1101 (2021/10/19)
N-Deacetylase/N-sulfotransferases (NDSTs) are critical enzymes in heparan sulfate (HS) biosynthesis. Radioactive labeling assays are the preferred methods to determine the N-sulfotransferase activity of NDST. In this study, we developed a fluorometric coupled enzyme assay that is suitable for the study of enzyme kinetics and inhibitory properties of drug candidates derived from a large-scale in silico screening targeting the sulfotransferase moiety of NDST1. The assay measures recombinant mouse NDST1 (mNDST1) sulfotransferase activity by employing its natural substrate adenosine 3′-phophoadenosine-5′-phosphosulfate (PAPS), a bacterial analog of desulphated human HS, Escherichia coli K5 capsular polysaccharide (K5), the fluorogenic substrate 4-methylumbelliferylsulfate and a double mutant of rat phenol sulfotransferase SULT1A1 K56ER68G. Enzyme kinetic analysis of mNDST1 performed with the coupled assay under steady state conditions at pH 6.8 and 37°C revealed Km (K5) 34.8 μM, Km (PAPS) 10.7 μM, Vmax (K5) 0.53 ± 0.13 nmol/min/μg enzyme, Vmax (PAPS) 0.69 ± 0.05 nmol/min/μg enzyme and the specific enzyme activity of 394 pmol/min/μg enzyme. The pH optimum of mNDST1 is pH 8.2. Our data indicate that mNDST1 is specific for K5 substrate. Finally, we showed that the mNDST1 coupled assay can be utilized to assess potential enzyme inhibitors for drug development.
A nano switch mechanism for the redox-responsive sulfotransferase
Lin, Chih-Heng,Lin, En-Shyh,Su, Tian-Mu,Hung, Kuo-Sheng,Yang, Yuh-Shyong
experimental part, p. 224 - 231 (2012/09/07)
Cellular redox signaling is important in diverse physiological and pathological processes. The activity of rat phenol sulfotransferase (rSULT1A1), which is important for the metabolism of hormone and drug, is subjected to redox regulation. Two cysteines, Cys232 and Cys66, nanometer away from each other and from the enzyme active site were proposed to form disulfide bond to regulate the activity of rSULT1A1. A nano switch, composed of a flexible loop from amino acid residues 59-70, explained how this long distance interaction between two cysteines can be achieved. The enzyme properties were investigated through site-directed muatagnesis, circular dichroism, enzyme kinetics and homologous modeling of the rSULT1A1 structures. We proposed that the formation of disulfide bond between Cys232 and Cys66 induced conformational changes of sulfotransferase, then in turn affected its nucleotide binding and enzyme activity. This discovery was extended to understand the possible redox regulation of other sulfotransferases from different organisms. The redox switch can be created in other redox-insensitive sulfotransferases, such as human phenol sulfotransferase (hSULT1A1) and human alcohol sulfotransferase (hSULT2A1), to produce mutant enzymes with redox regulation capacity. This study strongly suggested that redox regulation of drug and hormone metabolism can be significantly varied even though the sequence and structure of SULT1A1 of human and rat have a high degree of homology.
An improved one-pot synthesis of nucleoside 5'-triphosphate analogues
Gillerman, Irina,Fischer, Bilha
, p. 245 - 256 (2011/08/06)
Nucleoside 5'-triphosphate (NTP) analogues are valuable tools for biochemical and medicinal research. Therefore, a facile and efficient synthesis of NTP analogues is required. Here, we report on an improved nucleoside 5'-triphosphorylation procedure to obtain pure products after liquid chromotagrpahy (LC) separation with no need for high performance liquid chromatography (HPLC) purification. To improve the selectivity of the reaction we attempted the optimization of several parameters such as solvent, pyrophosphate nucleophilicity, time and temperature of the reaction. Eventually, the reaction was optimized by decreasing the temperature to -15°C and increasing the reaction time to 2 hours, based on monitoring time-dependent product distribution using 31P NMR. Furthermore, the NTPs were obtained as pure products after LC separation, which was impossible in the original Ludwig procedure. Good yields were obtained for all studied natural and synthetic nucleosides.