The optimum temperature of salicin hydrolysis by enzyme action is independent of the concentrations of substrate and enzyme / by Arthur Compton ; [communicated by Sir J.R. Bradford].

  • Compton, Arthur.
Date:
1914
Catalogue details

Licence: In copyright

Credit: The optimum temperature of salicin hydrolysis by enzyme action is independent of the concentrations of substrate and enzyme / by Arthur Compton ; [communicated by Sir J.R. Bradford]. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    Table II. Temperatures at the beginning and end of each experiment. Salicin hydrolysed. 0 per cent. 17 -8-17 -6 24 -2 29 -3-29 -5 42 -8 34 -7 50 -0 41 -8-41 -7 43 -0 50 -2-50 -3 31-4 57 -5-67 -6 16 -4 Next the activity of the enzyme was determined in the vicinity of +34° for a 15 hours’ action with each of the following concentrations of the substrate: M/5, M/10, M/15, M/30, and M/50, the effect of which on the optimum temperature of the enzyme it was ultimately intended to study. The temperature actually employed was 33'6°-33‘8°; and the experimental details were the same, except the dilutions, as already described for the preliminary determination. The numbers obtained are given in Table III. Table III. Quantity of enzyme. Salicin hydrolysed per cent, for the following concentrations:— M/5. M/10. M/15. M/30. M/50. mgrm. 0*5 31 -4 35 -8 28 -2 1 -0 55 T 57 -5 58 -5 49-5 36 -9 2-0 79 -4 84 -7 88 -7 77 -0 — 3 -0 88 -3 93 -9 97-6 90-0 77 -2 5-0 94-2 97 -5 99 -6 99 -0 93-9 7-0 94-9 96 -7 99 -2 100 -6 100 -0 10 0 95 -7 100 -2 99-6 — 100 -5 12 -5 95 -7 — 100 -6 100-6 100 -0 These numbers give, on plotting the percentage of salicin hydrolysed against the quantity of enzyme in play, the activity curves shown in fig. 3. The influence of the substrate concentration on the optimum temperature of the ferment, the fourth stage of the inquiry, may now be considered. This is the case of determining the optimum temperature in a series of experiments in which the concentration of the enzyme is kept constant while that of the substrate varies. The concentration of the enzyme chosen, in accordance with fig. 3, was 0'4 mgrm. in 5 cm.®, i.e. 8 x 10~® grm. per cm.® of the reaction mixture. Five different solutions of the enzyme were prepared