Differentiation of Disaccharide-splitting Enzymes

Leibowitz, J.; Hestrin, S.

doi:10.1038/143333b0

Cited by 3 publications

(7 citation statements)

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“…Experiments reported in the present and in previous investigations [Leibowitz & Hestrin, 1939;Schultz & Atkin, 1939;Kluyver & Custers, 1940] confirm that under suitable conditions maltose fermentation by yeast may be selectively inhibited or accelerated by agents which are without known similar or comparable influence on either glicozymase or maltase. The differential effects of certain sugars, hydrogen ion concentration, and oxygen on the fermentation of maltose and glucose by baker's yeast are compared in the following table.…”

Section: Discussionsupporting

confidence: 84%

“…The specific activating effect of zymohexoses and the retarding action of saccharides such as methyl oc-glucoside on maltolysis becomes comprehensible, on the other hand, if the view is accepted that maltose fermentation involves the specific participation of activators which are formed in the cell during and by the breakdown of fermentable sugar [Leibowitz & Hestrin, 1939]. The activation, it may be noted, persists long after the last trace of glucose has been exhausted by fermentation.…”

Section: Discussionmentioning

confidence: 99%

“…* Cf. preliminary note [Leibowitz & Hestrin, 1940], earlier investigation [Leibowitz & Hestrin, 1939], and dissertation by Hestrin [1941]. ( 772 ) DIRECT MALTOSE FERMENTATION long as b continues to set the pace, the presence of specific activators or inhibitors of maltolysis will not affect the rate of gas liberation.(3) Vm/ Vg> 1.…”

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confidence: 99%

“…DIRECT MALTOSE FERMENTATION of Willstatter & Rohdewald [1937;, that this metabolite is glycogen [Leibowitz & Hestrin, 1939]. The finding that certain preparations of phosphorylase may -act on maltose as well as on higher polysaccharides though not on glucose [Hanes, 1940;cf.…”

mentioning

confidence: 99%

“…The relative importance of the maltase-glucozymase complex and of maltozymase, respectively, in maltose fermentation by yeast is obviously dependent on a variety of factors including pH and temperature [cf. Leibowitz & Hestrin, 1939]. The two systems are not, however, necessarily of the nature of competitors, but act each in separate though overlapping pH ranges.…”

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The direct fermentation of maltose by yeast. 2

Leibowitz

Hestrin

1942

Biochemical Journal

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Discussion on the existence of disaccharide-specific zymase systerns appears to be enitering a new phase. The fermentative breakdown of maltose, sucrose, lactose and trehalose has been investigated in recent years from different directions. Nevertheless, the question whether hydrolysis is an indispensable preliminary to the fermentation of a disaccharide is still variously answered. Supporters of the view that disaccharide fermentation may be 'direct' have as a rule been content, hitherto, with negative proofs showing that oligases are not indispensable to disaccharide fermentation. There is clearly need, however, for a positive hypothesis concerning the mechanism whereby disaccharides could be fermented directly. * Cf. preliminary note [Leibowitz & Hestrin, 1940], earlier investigation [Leibowitz & Hestrin, 1939], and dissertation by Hestrin [1941]. ( 772 ) DIRECT MALTOSE FERMENTATION long as b continues to set the pace, the presence of specific activators or inhibitors of maltolysis will not affect the rate of gas liberation.(3) Vm/ Vg> 1. The simplest explanation of this case is to assume that a exists and that its velocity is greater than a', the latter being rate limiting for glucolysis but not for maltose fermentation. This interpretation is only necessary, however, under certain conditions. Their specification will not be necessary in the present connexion. As in case (2) the limiting part-reaction of maltose fermentation may be contained in b. While the latter remains limiting, specific activators and inhibitors of maltose fermentation need not necessarily affect the rate of gas liberation. Conditions as specified under (1) were found in baker's yeast; conditions as specified under ( 2) and (3) in a brewer's yeast. Methods Yeast. Except where otherwise stated, the yeast used for tests was a Palestinian brand of commercial baker's yeast supplied by Paca Ltd. Samples purchased at different dates were left to stand on ice for a number of days before use. This treatment lessened the fermentative power of the yeast to maltose, augmented the effect on maltose fermentation of exposure of the yeast to glucose, and enhanced certain inhibitory effects described in the sequel. Autofermentation was always found to be negligible. Samples of brewer's yeast, Rishon strain, were kindly provided by Dr Hayman of Palestine Brewery Ltd., Rishon.Sugars. All sugars used were of good quality and supplied by B.D.H. or Schering-Kahlbaum.Gasometers. Except where otherwise stated, fermentation was followed gasometrically using the apparatus described by Hestrin [1941]. Duplicate fermentation runs with this apparatus yielded results which were identical to within 3 %. Aqueous 30 % CaCl2

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Section: Discussionsupporting

confidence: 84%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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The direct fermentation of maltose by yeast. 2

Leibowitz

Hestrin

1942

Biochemical Journal

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Inactivation of Enzymes by Irradiation

Goldhaber

Leibowitz

1943

Nature

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The Relation of Enzymatic Adaptation to the Metabolism of Endogenous and Exogenous Substrates

Spiegelman

Reiner

Cohnberg

1947

Journal of General Physiology

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The source of energy for enzymatic adaptation has been investigated. Aerobically, it is found that the endogenous carbohydrate reserves may be used as such a source. In cells depleted of their reserves, the adaptive substrate itself can be oxidized even while it cannot be fermented, and so can serve as a source of energy for the adaptation to a fermentative mode of utilization. Anaerobically, adaptation may occur at the expense of stored energy-rich compounds, while the reserves and the adaptive substrate are now useless as fuel. Such compounds appear to be more plentiful in young than in old cells. The addition of any fermentable substrate, such as glucose, leads to rapid anaerobic adaptation. Experiments in which maltose-adapted cells are adapted anaerobically to galactose with the aid of a little added maltose, and conversely, show that fermentability is the criterion of usefulness for an exogenous substrate in aiding the adaptive process. None of the endogenous and exogenous energy sources which have been investigated will facilitate adaptation unless the adaptive substrate is present while they are being consumed. The significance of these findings and the adequacy of "activation" hypotheses to explain enzymatic adaptation has been discussed.

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Differentiation of Disaccharide-splitting Enzymes

Cited by 3 publications

References 2 publications

The direct fermentation of maltose by yeast. 2

The direct fermentation of maltose by yeast. 2

Inactivation of Enzymes by Irradiation

The Relation of Enzymatic Adaptation to the Metabolism of Endogenous and Exogenous Substrates

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