Photosynthetic organisms produce ATP and NADPH using light as an energy source and further utilize these cofactors during metabolism. Photosynthesis involves linear and cyclic electron flows; as the cyclic electron flow produces ATP more effectively than the linear electron flow without NADPH, the cell efficiently adjusts ATP and NADPH production using the two different pathways. Nevertheless, direct measurement of ATP and NADPH production during photosynthesis has been difficult. In the present study, the photosynthetic ATP and NADPH production rates of Synechocystis sp. PCC 6803 under three different single peak wavelength lights (blue: 470 nm, R630: 630 nm, and R680: 680 nm) were evaluated based on ¹³C-metabolic flux analysis (¹³C-MFA) by considering the mass balance of ATP and NADPH between photosynthesis and metabolism. The ratios of ATP/NADPH production via photosynthesis were estimated as 3.13, 1.70, and 2.10 under blue, R630, and R680 light conditions, respectively. Moreover, the linear and cyclic electron flow ratios were estimated to be 1.1–2.2, 0.2–0.5, and 0.5–1.0 under blue, R630, and R680 light conditions, respectively. The predicted linear and cyclic electron flow ratios were consistent with the excitation ratio between photosystems I and II, as observed in the steady-state fluorescence spectra.

光合生物利用光作为能源产生ATP和NADPH，并在代谢过程中进一步利用这些辅助因子。光合作用涉及线性和循环电子流。由于循环电子流比不带NADPH的线性电子流更有效地产生ATP，因此细胞可以通过两种不同途径有效地调节ATP和NADPH的产生。然而，在光合作用过程中直接测量ATP和NADPH的产量一直很困难。在本研究中，集胞藻的光合作用ATP和NADPH产生速率。基于¹³ C代谢通量分析（¹³进行了评估，在三种不同的单峰波长光（蓝色：470 nm，R630：630 nm和R680：680 nm）下对PCC 6803进行了评估（¹³C-MFA），考虑到光合作用和新陈代谢之间ATP和NADPH的质量平衡。在蓝色，R630和R680光照条件下，通过光合作用产生ATP / NADPH的比率分别估计为3.13、1.70和2.10。此外，在蓝色，R630和R680光照条件下，线性和循环电子流量比分别估计为1.1-2.2、0.2-0.5和0.5-1.0。稳态荧光光谱中观察到，预测的线性和循环电子流量比与光系统I和II之间的激发比一致。