The oxidases and other oxygen - catalysts concerned in biological oxidations / by J. H. Kastle.

  • Joseph Hoeing Kastle
Date:
[1910]
Catalogue details

Licence: In copyright

Credit: The oxidases and other oxygen - catalysts concerned in biological oxidations / by J. H. Kastle. Source: Wellcome Collection.

    114/168 (page 112)
    Quantitative studies of the oxidation of pyrogallol by hydrogen peroxide and a peroxidase have also been made by Bach and Chodat (31) with the following results: (1) [Pyrogallol, 1 gram; hydrogen peroxide, 0.1 gram; peroxidase, from 0.01 to 0.1 gram, in 50 c. c.] Peroxidase 0.01 0.02 0.03 0.04 0.05 0.06 0.07 0.08 Purpurogallin 0.021 0.042 0.0GG 0.-083 0.102 0.123 0.145 0.1G6 (2) [Pyrogallol, 1 gram; peroxidase, 0.1 gram; hydrogen peroxide, from 0.01 to 0.1 gram.] Peroxide 0.01 0.02 0.03 0.04 0.05 0.0G 0.07 0.08' Purpurogallin 0.020 0.042 0.060 0.078 0.099 0.121 0.142 0.1G8 (3) [Peroxidase, 0.1 gram; hydrogen peroxide, 0.1 gram; pyrogallol, 1 to 4 grams.] Pyrogallol 1.0 1.5 2.0 3.0 4.0 Purpurogallin 0.168 0.205 0.203 0.208 0.202 It would seem therefore that the amount of pyrogallol oxidized under these conditions is proportional to both the quantity of the peroxidase and of the hydrogen peroxide, but independent of the quantity of pyrogallol present, provided that the latter is in excess of the quantity capable of being oxidized within the given time by the several amounts of the peroxidase and hydrogen peroxide employed. NATURE AND MODE OF ACTION OF THE OXIDASES, PEROXIDASES AND CATALASES, AND THE CHEMICAL RELATIONSHIPS EXISTING AMONG THESE SUBSTANCES. The question still remains to be considered as to how these sub- stances act as oxygen carriers. We have seen that according to Schoenbein they react by ozonizing the oxygen of the air, and in the case of the peroxidases, by converting hydrogen peroxide, an anto- zonide, into an ozonide, after the manner of lead acetate. On the other hand, according to Bach (18) the oxidases are substances hav- ing a special aptitude for forming peroxides. Similar views have been advanced by Ivastle and Loevenhart (244). Thus according to the peroxide theory of oxidation, when molecular oxygen finds itself in contact with the complex autoxidizable substances contained in the plant cell, it combines with the same in much the same way that it unites with rubidium or benzaldehyde. There is produced under these circumstances a complex unstable peroxide which, in turn, can give up a part, if not all of its oxygen, to any oxidizable substance or acceptor that may happen to be present, or in the event that no other oxidizable substance is present, it may oxidize a part of itself.