Introduction 14 14 1954 1987 2004 1954 1954 14 14 14 14 1993 1978a ido altro 2 2 1 Fig. 1 d glycero- d ido- 1971 1978a 2004  2 1956 tentative 1974 1974 1962 1956 1982 d g d i 2 d glycero- d ido- 2 Fig. 2 2  ido- d glycero- d altro- d g d i 1 14 13 2 4 8 Materials and methods Growth of plant material Spinacia oleracea 1966 Chemical and chromatographic materials 14 32 Extraction and analysis of photosynthetic tissue metabolites by gas-liquid chromatography g g + 3 − 1984 Photosynthesis experiments with whole spinach leaves 14 1966 1989 1985 14 1987 Preparation of whole leaf homogenate g Chloroplast isolation 1983 −2 −1 4 2 7 2 2 1966 g 2 2 1966 n 2 −1 −1 n Chlorophyll assay 1949 1960 Measurements of chloroplast polarographic activity and intactness 2 2 i 3 2 2 −2 −1 −1 −1 1975 Isotopic tracer studies with isolated chloroplasts 14 3 2 1989 1985 1980 32 −1 1978b 1985 Preparation of stromal enzyme extracts (SEP) from spinach chloroplasts 1981 2 2 −1 −1 g g 2 1979 2 Assay of the reductive PP using stromal enzyme preparation (SEP) 1981 2 3 2 3 2 Maximum catalytic capacity of the non-oxidative segment of the PP 1984 + 2 Synthesis of isotopically labelled compounds 14 14 d g d a 14 d g d i 1987 32 altro 32 2 32 2 d glycero d ido d glycero d altro 2 1985 Measurements of phosphotransferase activity 1985 minimum d glycero d ido 2 d glycero d altro 2 d altro 1 2 1 \documentclass[12pt]{minimal}
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\begin{document}$$ [\hbox{8-}^{14}\hbox{C}]\hbox{-}{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct8-P}+\hbox{Seh 1,7-P}_{2}
\longleftrightarrow \hbox{Seh 7-P} + [\hbox{8-}^{14}\hbox{C}]\hbox{-}{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 1,8-P}_{2} $$\end{document} 2 \documentclass[12pt]{minimal}
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\begin{document}$$ [\hbox{8-}^{14}\hbox{C}]\hbox{-}{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}a\hbox{-oct 8-P}+\hbox{Seh 1,7-P}_{2}
\longleftrightarrow \hbox{Seh 7-P} + [\hbox{8-}^{14}\hbox{C}]\hbox{-}{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}a\hbox{-oct 1,8-P}_{2} $$\end{document} 14 −1 2 ° 4 4 14 1985 Arabinose 5-P activity with SEP 14 ° 14 1984 Positional isotopic analysis of sugar phosphates 14 d g d i 2 1968 1951 14 1959 14 Escherichia coli ° 1975 + 3 − 14 ° 14 14 2 1971 14 1985 14 1984 1970 14 1965 14 2 3 3 2 3 1962 Replication and statistical analysis Data presented are the mean values (±S.D.) from results of five or more experiments or mean values (±P.E.) (Probable Error) for all experiments conducted on different days. Results and discussion GLC analysis of perchloric acid extracts of spinach leaves ido altro d g d i 2 1959 1966 Primula officinalis 1996 d glycero d ido Craterostigma plantagineum 1984 Chlorella sorokiniana d g d i 1 d glycero d ido 2 3 Fig. 3 Gas liquid chromatogram of dephosphorylated TMSi-derivatized sugars extracted from young spinach leaves during light-driven carbon fixation. Octuloses and arabinose feature in the chromatogram. For details see Materials and methods section  d g d i d g d a −1 ido −1 altro 14 d g d i 2 14 2 d g d i 2 d g d i 2 14 2 1966 2 14 2 −2 −1 14 2 14 2 6 −1 −1 4 14 14 Fig. 4 14 14 2 14 14 A B A 14 B 2 d g d i 2  5 −1 −1 4 4 14 4 −1 −1 2 d g d i 2 3 3 −1 −1 14 4 14 2 Scenedesmus 1952 d g d i 2 14 −1 14 4 1966 14 2 12 2 14 12 12 2 5 6 14 2 5 Fig. 5 14 2 14 2 14 14  Fig. 6 14 2 4 A 2 d g d i 2 B  4 6 d g d i 2 14 2 12 2 14 14 d glycero d ido P 2 d g d i 2 d g d i 2 32 i 14 d g d i 2 14 14 3 32 d g d i 2 1980 32 32 d g d i 2 32 d g d i 2 −1 1977 d g d i 2 −1 ido- 1977 1978 1980 1980 1988 altro- 13 d g d i 2 14 2 14 d g d i 2 d g d i 2 \documentclass[12pt]{minimal}
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\begin{document}$$ \frac{\hbox{1.3 nmol per mg Chl}\times 1,000 \mu\hbox{l}}
{26\,\mu\hbox{l per mg Chl}}=\hbox{0.05 nmol per } \mu \hbox{l } (50\, \mu \hbox{M})
$$\end{document} d g d i 2 14 14 2 d g d i 3 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Glc 6-P + Fru 6-P}\mathop{\longleftrightarrow}\limits^{\rm TK} {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 8-P + Ery 4-P} $$\end{document} 4 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Ara 5-P + DHAP}\mathop{\longleftrightarrow}\limits^{\rm Ald} {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 1,8-P}_{2} $$\end{document} 5 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Ara 5-P + Fru 6-P}\mathop{\longleftrightarrow}\limits^{\rm TA}{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 8-P + GaP} $$\end{document} d g d i 2 1974 1987 d g d i d g d i 2 1985 6 \documentclass[12pt]{minimal}
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\begin{document}$$ {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 8-P + Seh 1,7-P}_{2} \mathop{\longleftrightarrow}\limits^{\rm PT} {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 1,8-P}_2 +\hbox{Seh 7-P} $$\end{document} 2 14 2 d g d i 2 14 d g d i 2 14 2 d g d i 2 14 1985 14 14 1 14 2 2 14 d g d i 2 14 2 Table 1 14 14 2 a Carbon 14 2 45 s 75 s 120 s Glc 6-P d g d i 2 Rib 5-P PGA Glc 6-P d g d i 2 Glc 6-P d g d i 2 Glc 6-P     Found Predicted                           1 3.2  35.6  (33.3)  23.4 84.9 12.7  20.4  (38.7) 15.1  29.9  (37.3) 18.5 2 3.2  25.3  (33.3) }  7.2 7.4  21.1  (22.6) 10.3  30.6  (25.4) 11.8 3 37.2  39.1  (33.3) 71.6 7.9 24.6  58.5  (38.7) 22.0  39.5  (37.3) 17.2 4 50.5  21.2  (3.1)   38.1  13.1  (8.5) 33.4  13.3  (12.1) 25.0 5 2.5 }  }   5.0  7.0 }  }  9.1 }  }  10.7 6 3.4 (60.7) (93.2)    10.2 79.2 (79.8) 10.1 63.7 (76.0) 17.1 7              8   18.1  (3.5)      7.7  (11.7)   23.0  (11.9)  14 88  b  c  86 101 106  b  c 93  b  c 90 a 14 2 b, c 14 d g d i 2 Table 2 14 a Carbon Percent specific radioactivity 40 s 60 s PGA DHAP Glc 6-P PGA Glc 6-P d g d i 2   Found   (Theory) 1 55.1 59.4 12.5 46.6 13.6  56.7  (32.5) 2 18.4 17.2 7.3 29.2 14.4  28.4  (35.0) 3 26.5 23.4 23.0 24.2 18.3  14.9  (32.5) 4   39.1  33.6  18.4  (17.0) 5   8.5  9.2 }  }  6   9.6  10.9 64.0 (70.0) 7        8       17.6  (13.0) 14 98 101 89 97 95  b c   a 14 −1 3 2 2 14 3 −1 b, c 14 d g d i 2 d g d i 14 14 d g d i 2 1 2 1 14 d g d i  14 d g d i 1 14 d g d i 2 d g d i 1 2 14 d g d i 2 14 ido- 2 14 1957 14 14 14 14 d d + x d g d i 2 d g d i 2 14 2 1 14 2 14 d g d i 2 14 1 14 2 14 d g d i 2 14 14 14 14 d g d i 2 1 2 14 14 d g d i 14 1 2 d g d i 14 2001 14 d g d i 2 1989 13 2 1966 13 d g d i 2 x 13 d g d i 2 13 13 d g d a 2 13 2 1987 d g d i 1977 14 Phaseolus vulgaris 14 2 d g d i 14 1978a d g d a ido Stromal enzyme preparation and photosynthesis 2+ 14 2 2 2 2 3 2 2 3 1981 Table 3 Rates of reductive PP sequences, measured by NADH oxidation, in reactions catalysed by spinach SEP with a variety of sugar phosphates as substrates Substrate Concentration (mM) −1 −1 a b 2 2.0 592 ± 79 (9) 546 Rib 5-P 2.0 743 ± 92 (10) 453 Rib 5-P 0.2 366 ± 39 (10) – Seh 7-P 2.0 183 ± 32 (12) 184 2 2.0 76 ± 14 (10) 112 2 2.0 10.1 ± 2.7 (10) 74.1 2 1.0 18.2 ± 2.9 (11) – Fru 6-P 2.0 c 77.6 Fru 6-P + DHAP 2.0/0.20 1.8 ± 0.4 (10) 142 Fru 6-P + PGA 2.0/0.20 2.9 ± 0.4 (8) – DHAP 2.0 13.1 ± 3.1 (10) 53 DHAP 0.20 5.0 ± 1.4 (11) 22.6 Ara 5-P 2.0 d – d g d i 2 2.0 3.7 ± 1.7 (5) – d g d a 2 2.0 9.3 ± 1.5 (6) – d g d i 2.0 6.3 ± 2.4 (5) – d g d a 2.0 8.2 ± 3.0 (5) – a b 1981 c −1 −1 d 2 2 2 1974 ido- altro- 2 3 1979 2 2 −1 −1 4 Table 4 Maximum catalytic activity of selected enzymes of the reductive PP in Spinach SEP Enzyme −1 −1 This study 1969 a 1990 2423 + b 207 269 c i j 194 d 113 102 e 53 46 f k 3.8 g l m – h 2.4 7.7 g n  g Chlorella fusca n  g n m  a, b 1969 c  1974 d 1974 e 1974 f 1982 g 1985 h 1974 i j k  i l 14 d g d i 2 m  14 d g d a 2 n d g d i 2 ND: not detected d g d a 2 3 ido d g d i 2 d g d i 2 d g d i 2 14 3 d g d a 2 2 d g d a 2 2 d g d a 2 3 d g d i 2 3 1981 2 slow 3 1974 2 Determination of the activity of the non-oxidative segment of the PP 1978b 1987 1 + −1 −1 n 1981 1979 −1 −1 1982 3 1 Phosphotransferase activity 2 1 1978a 1987 1980 1985 1954 2002 1987 Chlorella fusca 1985 4 13 14 d g d i 2 1989 14 2 d g d i d g d i 2 1971 1974 1985 1 2 d g d i 2 2 14 d g d i −1 −1 n 4 2 14 d g d a −1 −1 n 4 2 −1 −1 4 14 d g d a d g d i 2 4 1985 + 32 2 d g d i 32 32 d g d i 2 1985 2 32 2 32 d g d i 2 32 2 32 i 32 2 32 2 2+ 32 32 2 32 i d g d i 2 2+ minimum d g d i 32 2 2 32 32 d g d i 2 32 d g d i d g d i 2 −1 −1 1973 d g d i −1 −1 1977 d g d i 2 4 d g d a minimum 3 altro 2 2 1 Arabinose 5-phosphate reactions with spinach stromal enzyme preparation 1 d g d i 2 d g d i 2 2 2 3 2 2 14 7 Fig. 7 14 14 14 14 2 2 1985 p-i  14 14 14 R f 7 14 14 2 14 14 14 14 2+ K i 1978a d manno 1984 1987 K i 1984 14 3 14 −1 −1 14 3 2 2 2 1977 d 1987 1960 1984 1971 1989 1993 d g d i d g d a 7 \documentclass[12pt]{minimal}
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\begin{document}$$ {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 8-P + Rib 5-P } \mathop{\longleftrightarrow}\limits^{\rm TA-Exchange} \hbox{ Ara 5-P
+ }{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}a\hbox{-oct 8-P} $$\end{document} 8 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Ara 5-P}\mathop{\longleftrightarrow}\limits^{\rm Arabinose\,5-phosphate\,ketol-isomerase}\hbox{Ru 5-P} $$\end{document} 9 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Ru 5-P}\mathop{\longleftrightarrow}\limits^{\rm Ribose\,5-phosphate\,isomerase} \hbox{Rib 5-P} $$\end{document} 10 \documentclass[12pt]{minimal}
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\begin{document}$$ \hbox{Sum Reaction: }{\sc D}\hbox{-}g\hbox{-}{\sc D}{-}i\hbox{-oct 8-P}\longleftrightarrow {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}a\hbox{-oct 8-P} $$\end{document} 11 \documentclass[12pt]{minimal}
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\begin{document}$$ {\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}i\hbox{-oct 1,8-P}_{2} \hbox{+ Rib 5-P}\mathop{\longleftrightarrow}\limits^{\rm Ald-Exchange}
{\sc D}\hbox{-}g\hbox{-}{\sc D}\hbox{-}a\hbox{-oct 1,8-P}_{2} \hbox{+ Ara 5-P} $$\end{document} ido- altro ido- altro- 1989 1993 d g d i 2 d g d a 2 d g d a ido x x d glycero- d ido- 2 2 2 d g d i d g d a ido- d g d a 4 2 −1 −1 2 −1 −1 1 Scheme 1    ido- altro- 1 d glycero- d ido- d glycero- d altro- 1 d d g d a 2 2 3 d g d i 2 2