ABSTRACT
The effect of temperature on haemolytic systems in which saponin and sodium taurocholate respectively were used as lysins has been described by Ponder and Yeager (1930 a). They have found that in these cases the Arrhenius equation cannot be applied, mainly because of the complexity of these apparently simple systems.
It was originally my intention to continue this work using a homologous series of alcohols as lysins, since, as the alcohols are less complex in structure than either saponin or sodium taurocholate, the results obtained might be less difficult to analyse. Investigation, however, revealed that propyl alcohol was the only one in the entire series which could be dealt with successfully1. The temperature effect was studied at 3, 8·5, 27, 37 and 47° C., using propyl alcohol in varying dilutions as the lysin.
By the analysis used by Ponder and Yeager, it is possible to determine the order (i.e. the value of n) of the time-dilution curve for each temperature θ, and Table I shows the close agreement between the experimental and calculated values of t and also shows the values of n for each temperature 2
From the time-dilution curves we can obtain the values of x and c and by substitution in equation (1) it is possible to determine the value of k. The manner in which the different constants vary with the temperature is seen in Table II.
From this table it can be seen that the differences in velocity of lysis when the temperature is raised are due to changes in the values of the three constants, k, x and n. In such a case the Arrhenius equation cannot be applied, since it assumes that an increase in temperature is accompanied only by a change in the velocity constant, k.
If we plot the logarithm of the velocity against the reciprocal of the absolute temperature, the set of curves seen in Fig. 1 is obtained.
Ordinate log I/t; abscissa I/θ° absolute. The figures corresponding to each line denote the dilution of lysin used in the system.
If the effect of temperature were as the Arrhenius equation describes it, the points corresponding to different temperatures for one dilution of lysin should fall upon a straight line from which the temperature coefficient μ can be calculated. Inspection of Fig. I will show that the lines are neither straight nor parallel. Even if we consider that the points do fall on a straight line, the values of μ calculated from these lines, drawn through the mean of the plotted points, are found to range from 11,000 where the dilution is I in 5 to 50,000 where the dilution is I in 25. It is impossible to tell from these figures which value is the temperature coefficient for the entire reaction. It is even doubtful whether the temperature coefficient calculated for each dilution is correct, for at each temperature we are probably dealing with an entirely different system.
From the foregoing considerations, and especially from the fact that the constants x and p in equation (I) vary with temperature, and from the additional fact that log k is not linear with I/θ° (absolute), it is clear that the Arrhenius equation cannot adequately describe the effect of temperature on haemolytic systems containing propyl alcohol as the lysin. This is the conclusion reached by Ponder and Yeager for systems containing saponin and sodium taurocholate.
REFERENCES
Methyl, ethyl, and allyl alcohols react chemically with the haemoglobin in the cell and obscure the end points. Amyl and butyl alcohols are insufficiently soluble in water to produce results that are valid.
It was impossible to determine the order of the 47° C. time-dilution curve since at this temperature the end points became obscured after a short time, and only a small portion of the time-dilution curve could be plotted.
