Summary
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1)
In cotyledons of dry seeds from watermelons, 10 weak bands of MDH were detectable by electrophoresis (Fig. 1). After 3 hrs of germination, this pattern was reduced to 4 stronger bands whereas the total MDH activity remained unchanged. Artifacts were excluded by use of the reverse enzyme reaction (Fig. 2), different homogenizing media and mixing experiments.
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Molecular weight comparisons (Fig. 3) showed that with the exception of a glyoxysomal band (exclusion b Sephadex G-200) appearing at day 2 all bands and subbands had the same values (somewhat below 60000).
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3)
Homogenization of cotyledons from dry seeds with 10 mM β-mercaptoethanol resulted in a 4 band pattern (Fig. 8) identical to that found 3 hrs after sowing. Treatment of older cotyledons did not influence the later pattern. Electrophoresis of the raw extracts in presence of NAD or/and malate did not change the number of bands, only the RF-values. Dialysis of raw extracts was without influence.
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On the basis of these experiments it is concluded that during germination splitting processes of disulfide bridges take place which may result in conformation changes. According to this hypothesis dry seeds would contain 4 groups of conformational isoenzymes.
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Literatur
Anfinsen, C. B.: The formation and stabilization of protein structure. Biochem. J. 128, 737–749 (1972).
Bailey, L.: Techniques in protein chemistry, 2nd ed. Amsterdam: Elsevier Publ. Comp. 1967.
Bergmeyer, H. U. (Hrsg.): Methoden der enzymatischen Analyse, 2. Aufl., Bd. 1. Weinheim: Verlag Chemie 1970.
Brownlee, K. A. B.: Statistical theory and methodology in science and engineering. New York: Wiley 1965.
Chrambach, A., Rodbard, D.: Polyacrylamide gel electrophoresis. Science 172, 440–451 (1971).
Davis, B. J.: Disc electrophoresis. II. Method and application to human serum proteins. Ann. N. Y. Acad. Sci. 121, 404–427 (1964).
Epstein, Ch. J., Schechter, A. N.: An approach to the problem of conformational isozymes. Ann. N. Y. Acad. Sci. 151, 85–101 (1968).
Ferguson, K. A.: Starch-gel electrophoresis-application to the classification of pituitary proteins and polypeptides. Metabolism 13, 985–1002 (1964).
Fritz, P. J., Jacobsen, K. B.: Lactic dehydrogenases: subfractionation of isozymes. Science 140, 64–65 (1963).
Fritz, P. J., Jacobson, K. B.: Multiple molecular forms of lactate dehydrogenase. Biochemistry 4, 282–289 (1965).
Hedrick, J. L., Smith, A. S.: Size and charge isomer separation and estimation of molecular weights of proteins by disc gel electrophoresis. Arch. Biochem. Biophys. 126, 155–164 (1968).
Hock, B.: Die Hemmung der Isocitrat-Lyase bei Wassermelonenkeimlingen durch Weißlicht. Planta (Berl.) 85, 340–350 (1969).
Hock, B.: Veränderungen des MDH-Isoenzym-Spektrums bei der Samenkeimung der Wassermelone. Naturwissenschaften 58, 566–567 (1971).
Kaplan, N. O.: Nature of multiple molecular forms of enzymes. Ann. N. Y. Acad. Sci. 151: 382–399 (1968).
Kitto, G. B., Wasaarman, P. M., Michjeda, J., Kaplan, N. O.: Multiple forms of mitochondrial malate dehydrogenases. Biochem. biophys. Res. Commun. 22, 75–81 (1966).
Markert, C. L.: Lactate dehydrogenase isozymes: dissociation and recombination of subunits. Science 140, 1329–1330 (1963).
Munkres, K. D.: Genetic and epigenetic forms of malate dehydrogenase in Neurospora. Ann. N. Y. Acad. Sci. 151, 294–306 (1968).
O'Sullivan, S. A., Wedding, R. T.: Malate dehydrogenase isoenzymes from Cotton leaves. Molecular weights. Plant Physiol. 49, 117–123 (1972).
Racker, E.: Mechanism of action and properties of pyridine nucleotide-linked enzymes. Physiol. Rev. 35, 1–56 (1955).
Sachs, L.: Statistische Auswertungsmethoden, 3. Aufl. Berlin-Heidelberg-New York: Springer 1972.
Schweiger, H. G., Master, R. W. P., Werz, G.: Nuclear control of a cytoplasmic enzyme in Acetabularia. Nature (Lond.) 216, 554–557 (1967).
Wheat, T. E., Whitt, G. S.: In vivo and in vitro molecular hybridazation of malate dehydrogenase isozymes. Experientia (Basel) 27, 647–648 (1971).
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Hock, B. Isoenzyme der Malat-Dehydrogenase aus Wassermelonenkeimlingen: Mikroheterogenität und deren Aufhebung bei der Samenkeimung. Planta 110, 329–344 (1973). https://doi.org/10.1007/BF00387061
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DOI: https://doi.org/10.1007/BF00387061