. The chemical activities of bacteria. Bacteria. 78 THE FORMATION OF ENZYMES IN BACTERIA When the enzyme content of the culture is expressed on a basis of enzyme units per mgrm, dry weight of organism, we find two main types of variation with the age of the culture (Fig. 6). In the case of enzymes giving the Type I variation (Fig. 6), cultures taken as early as possible in the growth period have high activities, and these activities decrease as the culture grows, usually falling off rapidly after cell division has ceased. In the Type II variation, cells taken early in the growth period have li
. The chemical activities of bacteria. Bacteria. 78 THE FORMATION OF ENZYMES IN BACTERIA When the enzyme content of the culture is expressed on a basis of enzyme units per mgrm, dry weight of organism, we find two main types of variation with the age of the culture (Fig. 6). In the case of enzymes giving the Type I variation (Fig. 6), cultures taken as early as possible in the growth period have high activities, and these activities decrease as the culture grows, usually falling off rapidly after cell division has ceased. In the Type II variation, cells taken early in the growth period have little or no activity and the enzyme is formed during growth, reaching a maximum at about the time of cessation. AGE OF CULTURE Fig. 6. of cell division. After the end of the growth the activity may fall off, due to death of the cells, oxidation or digestion of the enzyme protein, etc. It is probable that we have not yet studied all the types of enzymes present in bacteria and the majority of those so far reported in the literature give a Type II variation with age of culture. These enzymes—deaminases, decarboxylases, dehydrogenases, etc.—are concerned with the breakdown of substrates with the liberation of carbon, nitrogen, energy, etc., and it does not follow that these enzymes have any direct connection with the synthetic processes of growth. Consequently it is possible that this Type II form of variation. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Gale, E. F. (Ernest Frederick). New York, Academic Press
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