Fl- .photoxidation, a quantum yield of 0.95 ± 0.05 was determined for production of the primary oxidized species called P 870 or P0.44. The extent of the cytochrome c photoxidation could be significantly increased by adding horse heart ferrocytochrome c and 1.5%

An effective and optimal combination of three reagents commonly used for modifying the structure of proteins has been developed for causing quantitative dissolution of membrane structure. Alkaline solution, 1.5 Triton X-100, and 6 M urea at 0" for about 2 hr causes quantitative conversion of chromatophores from wild-type Rhodopseudomoms spheroides into Triton-protein complexes having particle weights of less than 200,000. No trap activity is lost as evidenced by light-induced absorbance and electron paramagnetic resonance changes. Good rates for photoxida-

–Quantitative comparison of the decay rate for absorbance photochanges in chromatophores of R. rubrum at the major wavelengths of peaks and troughs (280, 365, 385, 433, 605, 763, 790, 810, 850, 865, 890 nm) reveal no major differences under a variety of sample conditions. In addition, the decay kinetics of EPR phtochange at the two environmental potentials used in this study are identical with the absorbance ph;otochange decay. Decay curves for fresh chromatophores, aged chromatophores, and fresh chromatophores at high ionic strength display a variety of half times and curve shapes. All of these data however, may be fit (within 10 per cent) by the equation x=αe8.2t+βe0.18t by merely varying the values of α and β. This is interpreted as meaning that any single trapping site may exist in one of two major forms each of which decays following a first order or pseudo‐first order reaction. Although the change in decay pattern upon aging is not reversible, that due to high ionic strength is. The time dependencies for two light emission phenomena have been measured as well as their response to the oxidation state of molecules at the trapping site. A major component of long‐lived luminescence follows pseudo‐second order kinetics with a half time of 38 msec. A very long lived luminescence shows an increse with time which is nearly proportional to the decay of absorbance photochanges.

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