The use of aryl azido ATP analogs as photoaffinity labels for myosin ATPase

Abstract
The synthesis of ATP analogs containing a photoactive aryl azido grouping coupled to the 3′ hydroxyl of ATP is described. The potential effectiveness of these analogs in the investigation of nucleotide‐binding regions is outlined and this effectiveness demonstrated by their photodependent inhibition of subfragment 1 ATPase. The use of 14C‐labeled azido ATP demonstrates an almost stoichiometric covalent binding of the analog.Because of their potential application to other systems, a number of reactions describing the reactivity of the 3′ hydroxyl of the nucleotide ribose are outlined in an Appendix.