A Kinetic Analysis of the Endogenous Respiration of Bakers' Yeast

Abstract

IWe will discuss in this paper the kinetics of endogenous respiration of bakers' yeast; that is, the respiration of intact yeast cells suspended in non-nutrient media. In succeeding papers results growing from an examination of the nature of the metabolic processes involved will be presented. The purpose of this series is to demonstrate the necessity of describing the behavior of metabolic systems at their native loci by the use of in vivo procedures. By dealing with experimentally verifiable rate-controlling steps in the various metabolic systems we will show how these complex chains of reactions may behave as distinct functional units at one time and, depending upon the imposed experimental conditions, as interrelated but yet coordinated systems. Since the overall metabolic activity can be shown to be governed by these rate-controlling "loci, ''1 integrated action of the myriads of simultaneous reactions is achieved within a cell. It is felt that this method of investigation is a necessary procedure which should precede any final application of the results of in vitro studies of enzyme action to the dynamical organization of in vivo metabolic processes.As a general rule in plant cells and tissues the rate of respiration under starvation conditions sooner or later decreases with time after the stored material has been reduced below a certain "critical concentra-1 Obviously in all but "zero order reactions" (for an example, cf. p. 471) the instantaneous rate of respiration may be a function of the concentration of reacting materials. The rate constant in these cases is then the appropriate constant describing the activity of the pace-setting locus; e.g., a first order constant. We imply that the behavior of the descriptive constant for the rate of decomposition of a relatively large amount of substrate reflects the physical and chemical characteristics of this locus, whatever its real nature may be.

ENDOGENOUS RESPIRATION OF STAPHYLOCOCCUS AUREUS

“…It has often been assumed that the endogenous substrate is either carbohydrate or lipid in nature (Reiner et al, 1949;Wilkinson, 1959). For example, Stier and Stannard (1936a) found an RQ of 1.0 for the endogenous respiration of yeast, and Bernheim (1954) noted that azide and dinitrophenol, which characteristically uncouple oxidation from phosphorylation, also increase the endogenous respiration of Mycobacterium tuberculosis. In the present study, an RQ value of 0.83 to 0.86 was observed, and the effect of azide and dinitrophenol on endogenous respiration was found to be negligible.…”

“…Relatively few studies have been made on the nature of endogenous respiration. Perhaps the first detailed study was that of Stier and Stannard (1936a), who noted that the rate of endogenous respiration of yeast declined with time. The decline was found to be characteristic of a firstorder process, was not due to enzyme deterioration, and evidence was obtained that the endogenous substrate was carbohydrate.…”

Technique in the Study of Yeast Assimilation Reactions

“…Otherwise i t is possible that false positives may appear, even in controls, and that the response to the test substance may be modified. I n fact, it is well established that the well fed yeast cell carries reserves of carbon as glycogen (Stier & Stannard, 1936), and of nitrogen compounds (Hartelius, 1934; Roine, 1947) ; and these reserves disappear as the yeast is starved. As yeasts have been grown on media nominally devoid of sulphur (Fulmer, Nelson & Sherwood, 1921), perhaps there is a sulphur reserve too, though the phenomenon may be due to traces of sulphur unwittingly included in the media (cf.…”

“…The work of Stier & Stannard (1936) suggested, however, that the carbohydrate reserve disappears within a few hours. On the other hand, for nitrogen assimilation, neither Wickerham (1946) nor Schultz & Pomper (1948) used starved yeasts, and they did not say they had trouble with their negative controls.…”

The Endogenous Respiration of Bacillus cereus

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This paper deals with the action of salts on respiration in the absence of substrate-the endogenous respiration of Stier and Stannard (1935). The use of substrates which permit cell division has been avoided because salts influence cell multiplication, creating difficulties in interpreting the results in terms of the effect of the salts upon respiration.

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