Abstract
Transketolase (E.C. 2.2.1.1.) has been partially purified from wheat (Triticum aestivum, cv. Sappo) and spinach (Spinacia oleracea) leaves. The fully-active enzyme is a tetramer of relative molecular mass (Mr) of 150 kMr requiring thiamin pyrophosphate for maximal activity, and dissociating into a 74 kMr dimer in its absence or in dilute solution. The chloroplastic transketolase (over 75% of the cellular total) is magnesium-stimulated but the cytosolic form is magnesium-insensitive. Both chloroplastic and cytosolic transketolase showed similar broad specificities towards several ketose phosphate substrates including fructose 6-phosphate and sedoheptulose 7-phosphate. Wheat and spinach leaf transketolases are not light-activated and closely resemble the yeast enzyme in many of their properties.
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Abbreviations
- Mr:
-
relative molecular mass
- TPP:
-
thiamin pyrophosphate
- Tris:
-
2-amino-2-(hydroxymethyl)-1,3-propandiol
References
Arnon, D.I. (1949) Copper enzymes in isolated chloroplasts. Polyphenol oxidase in Beta vulgaris. Plant Physiol 24, 1–15
Bennett, J. (1979) Chloroplast phosphoproteins. Phosphorylation of polypeptides of the light-harvest chlorophyll-protein complex. Eur. J. Biochem. 104, 85–89
Cavalieri, S.W., Neet, K.E., Sable, H.Z. (1975) Enzymes of pentose biosynthesis. The quaternary structure and reacting form of transketolase from baker's yeast. Arch. Biochem. Biophys. 171, 527–532
de la Haba, G., Leder, I., Racker, E. (1955) Crystalline transketolase from baker's yeast: isolation and properties. J. Biol. Chem. 214, 409–426
Delieu, T., Walker, D.A. (1972) An improved cathode for the measurement of photosynthetic oxygen evolution by isolated chloroplasts. New Phytol. 71, 201–225
Heinrich, C.P., Wiss, O. (1971) Subunit size of transketolase from baker's yeast. FEBS Lett. 14, 251–253
Kochetov, G.A., Minin, P.A. (1978) Isolation of transketolase from rat liver and some of its properties (in Russian). Biokhimija 43, 1631–1635
Latzko, E., Kelly, G.J. (1979) Enzymes of the reductive pentose phosphate cycle. In: Encyclopedia of plant physiology, N.S., vol. 6, pp. 239–250, Gibbs, M., Latzko, E., eds. Springer, Berlin Heidelberg New York
Lowry, O.H., Rosebrough, N.J., Farr, A.L., Randall, R.J. (1951) Protein assay with the Folin phenol reagent. J. Biol. Chem. 193, 265–275
Meshalkina, L.E., Kochetov, G.E. (1979) The functional identity of the active centres of transketolase. Biochim. Biophys. Acta 571, 218–223
Murphy, D.J., Walker, D.A. (1981) Aldolase from wheat leaves-its properties and subcellular distribution. FEBS Lett. 134, 163–166
Robinson, S.P., Walker, D.A. (1979) Rapid separation of the chloroplasts and cytoplasmic fractions from intact protoplasts. Arch. Biochem. Biophys. 196, 319–323
Villafranca, J.J., Axelrod, V. (1971) Heptulose synthesis from nonphosphorylated aldoses and ketoses by spinach transketolases. J. Biol. Chem. 246, 3126–3131
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Murphy, D.J., Walker, D.A. The properties of transketolase from photosynthetic tissue. Planta 155, 316–320 (1982). https://doi.org/10.1007/BF00429458
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DOI: https://doi.org/10.1007/BF00429458