Читать книгу Molecular Mechanisms of Photosynthesis - Robert E. Blankenship - Страница 55

So far, we have focused first on the overall process of photosynthesis and then on the discoveries leading up to the discovery of the series formulation of electron transport in oxygen‐evolving photosynthetic organisms, resulting in the reduction of NADP⁺ to NADPH. There is another critical part to the story, however, involving the light‐dependent formation of ATP and the subsequent utilization of these two products to reduce CO₂ to carbohydrates. The discoveries of these processes paralleled the discoveries of the electron transfer processes.

The discovery that chloroplasts could make ATP in a light‐dependent manner was made in 1954, by Daniel Arnon and coworkers at the University of California, Berkeley (Arnon et al., 1954). The idea that chloroplasts could make ATP, in a process called photophosphorylation, initially met with considerable resistance, because it was well known that mitochondria produced large amounts of ATP and, since chloroplasts in many ways drive the mitochondrial reaction in the opposite direction, this initially seemed backward (Arnon, 1984). An analogous discovery of light‐driven ATP formation in non‐oxygen‐evolving purple bacteria was made by Howard Gest and Martin Kamen (1948). The chemiosmotic hypothesis, the theoretical framework for the mechanism of how photon energy is stored in ATP, was provided by the incisive analysis of Peter Mitchell in the 1960s and 1970s, for which he received the Nobel prize in 1978 (Mitchell, 1979). We will discuss the details of the ATP synthesis process in Chapter 8.