The effect of dipyridamole on the interaction of photoactive bacteriochlorophyll with quinone acceptors reaction centers of purple bacteria

The action of dipyridamole, DIP, (10(-6)-10(-3) M) on the electron transfer in quinone Q(A)-Q(B) acceptor system and temporary stabilization of photom obilized electron on Q(B) in the reaction centers (RC) of Rb. sphaeroides w as studied. DIP addition call promote the increase of the time of electron transfer to Q(B). It depends on type of detergent in RC samples (lauryldime thylamine oxide, triton X-100, sodium dodecyl sulfate, sodium cholate). The DIP action on the effectivity of stabilization of photomobilized electron on Q(B) consisted in preferential increase of the time of photoactive bacte riochlorophyll dark recovery from Q(B). The DIP effect increased with the p H lowering (from 6;8-7,0 to 5,9-6,0). The possibility of modification of RC structural-dynamic state by DIP (including the change in RC hydrogen bonds ) is proposed. The modification obviously influences the functional activit y of the parameters studied.