Connexion between Carbohydrate and Potassium Metabolism in the Yeast Cell

Pulver, R; Verzár, F.

doi:10.1038/145823a0

Cited by 41 publications

(16 citation statements)

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“…Activation commences at 0-001 M and reaches its optimum at 0-07M, this activity range being almost identical with that recorded by Rothstein & Demis (1953) The studies on the effect ofK ions on carbohydrate fermentation and storage in yeast by Pulver & VerzAr (1940) caused Evans, Handley & Happold (1942) to study the effect of K ions upon the rate of development of tryptophanase activity in washed cells of E8ch. coli, which had been grown on glucosebouillon agar and then suspended in solutions of tryptophan buffered with phosphate.…”

Section: Resultssupporting

confidence: 80%

The activation of tryptophanase apo-enzyme by potassium, ammonium and rubidium ions

Happold

Struyvenberg

1954

Biochemical Journal

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Pyridoxal phosphate is the coenzyme to the tryptophanase apo-enzyme (Wood, Gunsalus & Umbreit, 1947; Dawes, Dawson & Happold, 1947), but its addition to dialysed enzyme preparations only effects a partial reactivation of the apo-enzyme, and this capacity to reactivate decreases as dialysis proceeds, as shown in the present communication.In previous studies in these laboratories we observed an apparent activation of tryptophanase by treatment with certain antisera other than anti-tryptophanase and then observed that this activating effect was shared with normal rabbit sera (Dolby, Hall & Happold, 1951); this activating effect was not destroyed by heating the serum to 1000 and was not due to any deficiency of pyridoxal phosphate. Two possibilities have been investigated in the present studies: (1) that removal of the coenzyme by dialysis allowed an irreversible inactivation of the apo-enzyme to occur, (2) that the enzyme complex requires other dialysable activators besides pyridoxal phosphate to complete the system. We have observed that ammonium, potassium and rubidium ions activate dialysed cell-free preparations of tryptophanase prepared from E8cherichia coli. EXPERIMENTALThe enzyme preparations used were obtained from acetonedried cells of E8ch. coli which had been grown for 18 hr. at 370 on casein digest agar medium (Dawes et al. 1947). The dried cells were extracted overnight at 370 with a solution of 0-8M-KCI (40 mg. dried cells/ml. solvent). The activity of the enzyme was determined by measuring the initial rate of indole formation in a total volume of 2-5 ml. comprised of 0 5 ml. enzyme preparation, 1 ml. 0 1 m sodium phosphate buffer (pH 7 8), 2 mg. L-tryptophan and to which was added distilled water with or without different ions and with or without l10ug. pyridoxal phosphate. When conditions have been varied the variation is stated. The enzymic activity of the preparations was determined by the method of Gooder & Happold (1954) and is expressed in terms of the indole produced in the above system during the initial 7 min. at 37°. The reaction was stopped by the addition of two drops of 40% formaldehyde instead of the trichloroacetic acid previously used. The cations tested were added as chlorides (0-5 ml. solution); the final concentration of the cation was therefore one-fifth of that added. Enzyme preparations were dialysed in cellophan bags rotated at an angle of 45°in the dialysing liquid; an air bubble and a few glass beads were provided in the bag to increase the circulation of its contents (Spiegelman, Reiner & Morgan, 1947). As dialysis of these preparations at room temperature resulted in rapid inactivation of the enzyme, this procedure was carried through at 20. RESULTSDialysis of the enzyme against distilled water. The results presented in Fig. 1 shows that the rate of inactivation of the enzyme increased progressively as the period ofdialysis was prolonged. Inactivation was complete in 3 hr. and in some experiments much sooner. After 45 min. dialysis, complete activity was restored by the ad...

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Section: Resultssupporting

confidence: 80%

The activation of tryptophanase apo-enzyme by potassium, ammonium and rubidium ions

Happold

Struyvenberg

1954

Biochemical Journal

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“…6) on the basis that the synthetic reactions leading to polysaccharide demand significant amounts of magnesium and phosphate. Similarly, the participation of potassium in polysaccharide synthesis (Pulver & Verzar, 1940 ;Duguid & Wilkinson, 1954) may account for the low RNA/K+ molar ratio at low growth rates. The observation that even the K+/Mg + and P/K+ ratios at dilution rates of 0.09 and 0-18 hr-l were respectively higher and lower than predicted by the 1 : 4 : 8 stoichiometry between magnesium, potassium and phosphorus, suggests that the proportion of cellular potassium K , Mq, P and RNA in A .…”

Section: Discussionmentioning

confidence: 99%

“…The importance of potassium in certain enzyme-catalysed reactions (Dixon & Webb, 1964), particularly those which involve phosphate transfer (Lardy, 1951) may explain its frequently reported participation in carbohydrate metabolism (Pulver & Verzar, 1940 ;Roberts, Roberts & Cowie, 1949;Eddy & Hinshelwood, 1951 ;Duguid & Wilkinson, 1954) and respiration (Krebs, Whittam & Hems, 1957;Perry & Evans, 1961;Blond & Whittam, 1965). It seemed justifiable, however, to inquire whether these catalytic roles demand the presence of potassium in growing cells in concentrations which make it the major metal nutrient.…”

Section: Introductionmentioning

confidence: 99%

The Influence of Temperature and Growth Rate on the Quantitative Relationship Between Potassium, Magnesium, Phosphorus and Ribonucleic Acid of Aerobacter aerogenes Growing in a Chemostat

Dicks

Tempest

1966

Journal of General Microbiology

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SUMMARYThe variations in potassium, magnesium and phosphorus contents of Aerobacter aerogenes grown in a chemostat, were measured as functions of the RNA content of the organisms. The RNA content was varied by altering temperature a t a fixed dilution rate under potassium-limiting conditions, and by varying the growth rate a t a fixed temperature under conditions of both magnesium-and phosphate-limitation. Changes in RNA were accompanied by corresponding changes in these other cellular components such that a molar stoichiometry close to 1 : 4 : 5 : 8 for magnesium, potassium, RNA (nucleotide) and phosphorus, respectively, was maintained. The only significant deviation from this ratio was observed in phosphatelimited organisms a t low growth rates ; these organisms possessed considerable amounts of carbohydrate. It is suggested that potassium, magnesium and phosphate are implicated in polysaccharide synthesis, thus changing the quantitative relationship between these three components and RNA previously observed. The results support the suggestion that most of the potassium in growing A . aerogenes is required to maintain the functional state of ribosomal particles.

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“…Uptake may equally well be by metabolic binding, in the cytoplasm, of ions which move into the cell by diffusion. Pulver & VerzAr (1940) observed that when yeast cells were placed in a potassiumfree medium about one-third of the potassium in the cells rapidly diffused out. Upon subsequent incubation with glucose, potassium was reabsorbed during a brief period in which glucose also was taken up.…”

Section: (C) Yeastsmentioning

confidence: 99%

Salt Uptake in Plants

Sutcliffe

1959

Biological Reviews

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Connexion between Carbohydrate and Potassium Metabolism in the Yeast Cell

Cited by 41 publications

References 1 publication

The activation of tryptophanase apo-enzyme by potassium, ammonium and rubidium ions

The activation of tryptophanase apo-enzyme by potassium, ammonium and rubidium ions

The Influence of Temperature and Growth Rate on the Quantitative Relationship Between Potassium, Magnesium, Phosphorus and Ribonucleic Acid of Aerobacter aerogenes Growing in a Chemostat

Salt Uptake in Plants

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