Design and synthesis of a new class of fluorescent photoaffinity label with specific reference to 4-benzoyl-1-benzamidofluorescein: a new photolabel for adenine nucleotide binding domains on enzymes

摘要

Benzophenone was used as the photoreactive moiety in the synthesis of several water soluble, fluorescent photoaffinity labels. The following compounds were synthesized: 5-(2-(p-benzoylbenzamido)ethylamino-1-napthalenesulfonate (BzEDANS); 5-(2-(p-benzoylbenzamido)hexylamino-1-napthalenesulfonate (BzHDANS); and 4-benzoyl-1-benzamidofluorescein (BzAF). BzEDANS and BzHDANS were found to be unsuitable for use as photochemical probes. They were incapable of photoinduced covalent binding to methylene carbon due to intramolecular triplet-triplet energy transfer. BzAF was synthesized because its fluorescent moiety, fluorescein, is an inefficient acceptor for intramolecular quenching of the benzophenone triplet state diradical intermediate. BzAF was found to be a suitable and efficient photolabel and is presently a prototype for a new class of fluorescent photolabel.