Summary
In extension of previous studies on the regulation of the aromatic amino acid pathway in blue-green and green algae the control of two branch-point enzymes, namely chorismate mutase and anthranilate synthetase has been studied. The activity of chorismate mutase in these organisms is effectively inhibited by l-tyrosine or l-phenylalanine. l-tryptophan, in contrast, proved to be a positive effector of the enzyme: in the absence of phenylalanine or tyrosine tryptophan slightly stimulated chorismate mutase activity; this stimulation was even brought about in the presence of excess phenylalanine or tyrosine, irrespective if the enzyme had been preincubated with these inhibitors or not. Tryptophan thus proved to completely revert the feedback inhibition of this enzyme by phenylalanine or tyrosine. Substrate saturation curves of chorismate mutase activity are hyperbolic in the presence of tryptophan and sigmoid in the presence of phenylalanine or tyrosine. In contrast to the enzymes of the green algae investigated, chorismate mutase activity of Anacystis nidulans, a member of the class of the blue-green algae was not affected by any of the aromatic amino acids.
The activity of anthranilate synthetase, the second enzyme of the chorismic acid branch-point of the pathway was consistently inhibited by l-tryptophan in all the organisms tested. The results described here bear significance on the regulation of a multi-branched pathway the first enzyme of which is inhibited just by one endproduct.
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Ames, B. N., R. G. Martin, and B. J. Garry: The first step of histidine biosynthesis. J. biol. Chem. 236, 2019–2026 (1961).
Baker, T. J.: Tryptophan: a feedback activator for chorismate mutase from Neurospora. Biochemistry 5, 2654–2657 (1966).
Gibson, F.: Chorismic Acid: Purification and some chemical and physical studies. Biochem. J. 90, 256–261 (1964).
Gibson, M. I., and F. Gibson: Preliminary studies on the isolation and metabolism of an intermediate in aromatic biosynthesis: Chorismic acid. Biochem. J. 90, 248–256 (1964).
Jensen, R. A., D. S. Nasser and E. W. Nester: Comparative control of a branch-point enzyme in microorganisms. J. Bact. 94, 1582–1593 (1967).
Lin, E. C. C., B. M. Pitt, M. Civen, and W. E. Knox: The assay of aromatic amino acid transaminations and keto acid oxidation by the enol borate-tautomerase method. J. biol. Chem. 233, 668–673 (1958).
Lingens, F., W. Goebel u. H. Uessler: Regulation der Biosynthese der aromatischen Aminosäuren in Saccharomyces cerevisiae. II. Repression, Induktion und Aktivierung. Europ. J. Biochem. 1, 363–374 (1967a).
———: Regulation der Biosynthese der aromatischen Aminosäuren in Claviceps paspali. European J. Biochem. 2, 442–447 (1967b).
Lowry, O. H., N. J. Rosebrough, A. L. Farr, and R. J. Randall: Protein measurement with the Folin phenol reagent. J. biol. Chem. 193, 265–275 (1951).
Monod, J., J. Wyman, and J. P. Changeux: On the nature of allosteric transitions: A plausible model. J. molec. Biol. 12, 88–118 (1965).
Nester, E. W., and R. A. Jensen: Control of aromatic acid biosynthesis in Bacillus subtilis: Sequential feedback inhibition. J. Bact. 91, 1594–1598 (1966).
Pringsheim, E. G.: Kleine Mitteilungen über Flagellaten und Algen. XVI. Lauterbornia (Anacystis) nidulans (Richter) nov. gen., nov. comb. Cyanophyceae. Arch. Mikrobiol. 63, 1–6 (1968).
Ruppel, H. G.: Untersuchungen über die Zusammensetzung von Chlorella bei Synchronisation im Licht-Dunkel-Wechsel. Flora (Jena) 152, 113–138 (1962).
Singh, R. N., and H. N. Singh: Ultra violet induced mutants of blue-green algae. I. Anabaena cycadeae Reinke. Arch. Mikrobiol. 48, 109–117 (1964).
Spiess, E., u. G. Richter: Die Nucleinsäuren grüner und gebleichter Zellen von Euglena gracilis. Arch. Mikrobiol. 53, 195–207 (1966).
Weber, H. L., and A. Böck: Comparative studies on the regulation of DAHP synthetase activity in blue-green and green algae. Arch. Mikrobiol. 61, 159–168 (1968).
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Weber, H.L., Böck, A. Regulation of the chorismic acid branch-point in aromatic acid synthesis in blue-green and green algae. Archiv. Mikrobiol. 66, 250–258 (1969). https://doi.org/10.1007/BF00412057
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DOI: https://doi.org/10.1007/BF00412057