Chorismat-Mutase aus Claviceps, I. Eigenschaften der Chorismat-Mutase aus verschiedenen Claviceps-Stämmen

Sprössler, Bruno; Lingens, Franz

doi:10.1515/bchm2.1970.351.1.448

Cited by 18 publications

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“…Chorismate mutase from Euglena gracilis is a single enzyme, the activity of which is inhibited by phenylalanine and tyrosine and is activated by tryptophan (23). The same pattern of feedback inhibition and activation was found in Neurospora crassa (1), Claviceps paspali (22), and Saccharomyces cerevisiae (14). Chorismate mutase of S. aureofaciens is not associated with prephenate dehydrogenase, prephenate dehydratase, or anthranilate synthetase activities and appears to be a single enzyme.…”

Section: Froction Numbersupporting

confidence: 54%

“…Feedback inhibition of enzymic a( S. aureofaciens chorismate mutase, enzyme of the terminal biosynthetic p phenylalanine and tyrosine, after th ing-point chorismic acid, is not inh phenylalanine and tyrosine. The 1 product of the aromatic amino acid bi( pathway, tryptophan, also does not activity of chorismate mutase in S. aureofaciens, whereas in Saccharomyces cerevisiae (15), Claviceps paspali (22), and Neurospora crassa (1) it is a strong activator of this enzyme. Metabolites of the biosynthetic pathway like shikimic acid, anthranilic acid, phenylpyruvic acid, and p-hydroxy-phenylpyruvic acid also do not influence the enzyme activity.…”

Section: Resultsmentioning

confidence: 97%

“…1). Chorismate mutase, the first enzyme of the terminal biosynthesis of phenylalanine and tyrosine, has been studied in a variety of organisms (1, 2,8,14,19,[21][22][23]). This paper diescribes the properties of chorismate mutase from Streptomyces aureofaciens.…”

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Chorismate Mutase from Streptomyces aureofaciens: a Heat-Stable Enzyme

Görisch¹,

Lingens²

1973

Journal of Bacteriology

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Chorismate mutase from Streptomyces aureofaciens was purified 12-fold. This enzyme preparation did not show any activity when tested for anthranilate synthetase, prephenate dehydrogenase, or prephenate dehydratase. The catalytic activity of chorismate mutase has a broad optimum between pH 7 and 8. The initial velocity data followed regular Michaelis-Menten kinetics with a K. of 5.3 x 10-I M, and the molecular weight of the enzyme was determined by sucrose gradient centrifugation to be 50,000. Heat inactivation of chorismate mutase, which occurs above temperatures of 60 C, is reversible. The enzyme activity can be restored even when chorismate mutase is treated at the temperature of a boiling-water bath for 15 min. Heat-denatured and renatured enzymes showed the same Michaelis constant and the same molecular weight as the native enzyme. L-Phenylalanine, L-tyrosine, L-tryptophan, and metabolites of the aromatic amino acid pathway were tested as potential modifiers of chorismate mutase activity. The activity of the enzyme was inhibited by none of these substances. Chorismate mutase of S. aureofaciens was not repressed in cells grown in minimal medium supplemented with L-phenylalanine, L-tyrosine, or L-tryptophan.

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Section: Froction Numbersupporting

confidence: 54%

Section: Resultsmentioning

confidence: 97%

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Chorismate Mutase from Streptomyces aureofaciens: a Heat-Stable Enzyme

Görisch¹,

Lingens²

1973

Journal of Bacteriology

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“…In contrast, the enzyme from the blue-green alga, Anacystis nidulans, did not exhibit in vitro regulation by any of the three aromatic amino acids. Preparations from Claviceps paspali were chromatographically separated into two distinct fractions with chorismate mutase activity (14). One fraction showed activation by L-tryptophan and inhibition by L-tyrosine and L-phenylalanine.…”

Section: Discussionmentioning

confidence: 99%

Regulation of Aromatic Amino Acid Biosynthesis in Higher Plants

et al. 1972

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Etiolated mung bean seedlings were examined for chorismate mutase activity. Evidence for the occurrence of two forms of the enzyme (designated CM-1 and CM-2) was obtained by ammonium sulfate fractionation, anion exchange cellulose chromatography, and isoelectric focusing. The two forms showed distinctly different properties, as CM-1 was inhibited by phenylalanine and tyrosine and activated by tryptophan, but inhibition by phenylalanine and tyrosine was reversed by tryptophan. The other form, CM-2, was unaffected by any of the three aromatic amino acids. Isoelectric points of the two forms were CM-1, pH 4.6, and CM-2, pH 5.6. The molecular weights estimated by molecular sieving on Sephadex G-200 were CM-1, 50,000, and CM-2, 36,000.Chorismic acid has been established as an important intermediate in the biosynthesis of the aromatic amino acids phenylalanine, tyrosine, and tryptophan in microorganisms (5-7). By action of chorismate mutase, chorismate is converted to prephenate, the precursor of phenylalanine and tyrosine. Chorismate serves as a substrate for anthranilate synthetase, the first reaction in a branch pathway leading to the synthesis of tryptophan. Control of chorismate mutase activity would therefore be of prime importance in the regulation of phenylalanine and tyrosine biosynthesis. Multiple forms of chorismate mutase have been found in fungi, bacteria, and blue green algae. Certain of these forms appear to have regulatory properties, and their roles in regulating production of the two amino acids have been investigated in these microorganisms (2, 3, 8-14, 16, 17 MATERIALS AND METHODSPlant Material. Etiolated mung bean seedlings (Phaseolus aureus) were purchased from a local retail grocer. Such seedlings germinated in the laboratory and harvested 2 to 3 days after planting gave the same results as those obtained commercially.Preparation of Acetone Powders. Whole seedlings were added to a Waring Blendor and ground for 1 min with acetone precooled to -10 C. The resulting suspension was put on a Biichner funnel and washed with cold acetone until the filtrate was colorless. The acetone powder was air-dried and then stored in a desiccator at 4 C under nitrogen. Powders stored for 2 weeks retained at least 80% of chorismate mutase activity that was present at the time the powders were prepared. Those stored for 1 month possessed only one-half of their original activity.Preparation of Pulverized Frozen Material. Etiolated mung bean seedlings were frozen in liquid nitrogen and, while frozen, homogenized to a fine powder in a Waring Blendor. At least 60 sec at full speed were required to pulverize completely the frozen material. The powder was stored at -10 C until used for enzyme extraction. Powders stored at -10 C for 1 month retained at least 95% of their original chorismate mutase activity.Enzyme Preparation. Frozen powder was mixed with 20% by weight Polyclar AT and 50 mm potassium phosphate buffer. pH 6.8, 5 g fresh weight of powder per ml of buffer. The powder was allowed to thaw and then left ...

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Regulation von Schlüsselenzymen der Biosynthese aromatischer Aminosäuren in Alkaloid‐bildenden Kulturen von Penicillium cyclopium w.

Schmauder

Roos

1987

J. Basic Microbiol.

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In Penicdlium cyclopium w., phenylalanin and anthranilate are precursors of the benzodiazepine alkaloids cyclopenin and cyclopenol. The onset and increase of alkaloid biosynthesis in emerged cultures was paralleled by an increase of the in vitro activities of the precursor synthesizing enzymes DAHP synthase'), chorismate mutase, and anthranilate synthase as well as tryptophan synthase. This increase was most pronounced with the DAHP synthase and, therefore, enabled the cells to maintain a constant level of the "central" precursor, chorismate, in the course of alkaloid production. In contrast, the contents of phe, anthranilate as well as tyr and trp decreased with increasing rate of alkaloid synthesis, indicating that the supply of the immediate precursors did not fully compensate the drain towards alkaloid formation. The strongest decrease was seen with the anthranilate content, which was due to several control mechanisms: the increase of anthranilate consuming reactions prior to the anthranilate synthase, the higher capacity of the alternate, phe producing branch of the aromatic pathway, and the feedback inhibition by trp of anthranilate synthase. The formation of anthranilate most probably was the rate limiting step of alkaloid production.

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Chorismat-Mutase aus Claviceps, I. Eigenschaften der Chorismat-Mutase aus verschiedenen Claviceps-Stämmen

Cited by 18 publications

References 0 publications

Chorismate Mutase from Streptomyces aureofaciens: a Heat-Stable Enzyme

Chorismate Mutase from Streptomyces aureofaciens: a Heat-Stable Enzyme

Regulation of Aromatic Amino Acid Biosynthesis in Higher Plants

Regulation von Schlüsselenzymen der Biosynthese aromatischer Aminosäuren in Alkaloid‐bildenden Kulturen von Penicillium cyclopium w.

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