Cell Structure and Cell Activity

The work of Batelli and Stern and of of Warburg has made clear the importance of surface structures in tissue oxidations, and a survey of oxidation systems as a whole show that there must be a considerable grading in complexity and stability of such structures. Agents such as those which oxidise the purine bases or aldehydes, are extractable from the cell; others have not yet been dissociated from the tissues. So many enzymes can be extracted from the cell only by means which must inevitably affect its structure that its is surprising to find that cell activity (or activity of its catalysts) is at all dependent upon cell structure. Disintegration of a cell, the breaking down of cell membranes, will certainly bring about as A. V. Hill (1928) has pointed out, a biochemical chaos and a medley of reactions. Catalysts will be brought into contact with substrates previously held remote from them. The cell end products will change in type and quantity. But if by activity of a cell is meant the activity of its catalysts, mechanical disintegration of the cell will not, in itself, be expressed to bring about any pronounced change. Muscle ground with sand exhibits a very good oxygen uptake in presence of para-phenylenediamine (Keilin, 1929). A number of de-hydrogenases may be extracted from tissues by shaking or maceration in saline or alkaline phosphate solution. Succinic dehydrogenase can be obtained from muscle and lactic dehydrogenase from yeast in this way. Oxidases of compounds of the aromatic type, e. g. , catechol oxidase or tyrosinase appear to act independently of the cell as a whole; so do peroxidase and the hydrolytic ferments. Failure to extract any enzyme would seem to be due to ignorance of a suitable method of elution from the tissue.