RESUMEN
The reaction centers are isolated from chromatophores of Rhodobacter sphaeroides 601 by detergent LDAO, and purified by chromatography on a DEAE-52 cellulose column. In the presence of acetone and an access of free pheophytins (Phes), bacteriopheophytins (Bphes) in reaction centers are replaced by pheophytins at sites H(A) and H(B) when incubated under high temperature. The substituting amounts are about 50% and 71% Bphes in reaction centers with incubation of fifteen and sixty minutes respectively. In the absorption spectra of reaction centers containing Phes (Phe RC), the Q(X) 537 nm and Q(Y) 758 nm bands of Bphe disappeared, three distinct bands assigned to the Q(X 509/542 nm and QY) 674 nm bands of phe appeared. Compared to reaction centers in control, the photochemical activities of Phe RCs, with incubating time of fifteen and sixty minutes, drop to 78 and 71% of that in control respectively.
