Spectrofluorometry of pyridine nucleotide reactions in Chromatium

Simultaneous measurement of changes in red and blue fluorescence in illuminated isolated chloroplasts and leaf pieces: The contribution of NADPH to the blue fluorescence signal

“…As the rate of photosynthesis increases, the couple becomes more oxidized. This behavior is not restricted to spinach, and has been observed in systems as different as pea (Foyer et al 1992), a C3 plant like spinach, maize (Rebeille and Hach 1986), a C4 plant, and Chromatium (Olson et al 1959), a photosynthetic bacterium having NAD for cofactor. It confirms the notion (Takahama et al 1981, Heber et al 1982) that during photosynthesis the pyridine nucleotides are more reduced when the phosphorylation potential is low, or P G A / D H A P ratio is low, and may then preferentially carry the load of carbon reduction.…”

“…Like NADH, when excited with UV light, NADPH fluoresces blue light with a peak at 460 nm (Harvey et al 1972). This property was used to follow pyridine nucleotides in algae and photosynthetic bacteria (Duysens and Amesz 1957, Duysens and Sweep 1957, Olson et al 1959, Olson and Amesz 1960, and was further developed in biomedical sciences (see for example Nuutinen 1984, Koretsky and Balaban 1987, Eng et al 1989) but was not applied to higher plants, most probably because of the omnipresence of chlorophyll and the UV absorbing epidermis. Pyridine nucleotides were estimated in leaves (Anderson andVennesland 1954, Foyer et al 1992), leaf compartments (Heber and Santarius 1965, Muto et al 1981, Usuda 1988, Heineke et al 1991, Laisk et al 1991, protoplasts (Hampp 1984) and isolated chloroplasts (Krogmann 1958, Das and Crane 1961, Lendzian and Bassham 1976, Takahama et al 1981, Heber et al 1982, Dietz and Heber 1984, Rebeille and Hach 1986 mainly by using enzymatic cycling after acid/base extraction.…”

Time-resolved spectroscopy of the blue fluorescence of spinach leaves

“…Several authors have established that under UV excitation, a fluorescence band with an emission maximum near 440 nm is detectable in baker's yeast, photosynthetic bacteria and algae, more probably due to bound reduced pyridine nucleotide (NADH, NADPH) (Duysens and Amesz 1957, Duysens and Sweep 1957, Olson et al 1959, Olson and Amesz 1960. They also showed that this fluorescence band has an excitation maximum at 280 and 340 nm.…”