2.8.1.4 ATP - 643806, 643807, 643808, 643809, 643810, 643812 2.8.1.4 ATP absolute requirement, other nucleotides are inactive 643805 2.8.1.4 additional information beta-mercaptopyruvate is inactive either as a cofactor or as a sulfur donor 643806 2.8.1.4 additional information sulfur transfer obtained with ADP is apparently due to the formation of ATP by the reaction 2 ADP = ATP + AMP, AMP is totally inactive as activating nucleotide 643808 2.8.1.4 additional information the enzyme requires two conserved Cys residues (Cys265 and Cys268), which are arranged in a CXXC motif in the PP-loop domain, for both in vitro and in vivo activities to generate 4-thiouridine in tRNAs 725494 2.8.1.4 pyridoxal 5'-phosphate - 643809