scholarly journals STUDIES ON THE ENZYMES OF PNEUMOCOCCUS

1920 ◽  
Vol 32 (5) ◽  
pp. 571-582 ◽  
Author(s):  
O. T. Avery ◽  
Glenn E. Cullen
Keyword(s):  
Enzyme Activity ◽  
Lipolytic Activity ◽  
Maximum Activity ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Intracellular Enzyme ◽  
Optimum Reaction

1. Pneumococci contain an intracellular enzyme of marked lipolytic activity as measured by the acid liberated by its action on tributyrin. 2. Enzyme-containing solutions may be prepared by dissolving pneumococci in bile, or by extraction by other means. 3. The optimum reaction for maximum activity of the endolipase is about pH 7.8, which coincides with the optimum hydrogen ion concentration for growth of pneumococci. 4. Heating the enzyme for 10 minutes at 70°C. destroys its activity. 5. Attenuation of virulence of pneumococcus had no measureable effect on enzyme activity. 6. The possible relation of the endolipase to the mechanism of bile solubility is discussed.

scholarly journals CHEMICAL CHANGES OF THE PAPAYA PLANT DURING DEVELOPMENT, WITH SPECIAL REFERENCE TO ITS PROTEOLYTIC ACTIVITY

1969 ◽  
Vol 27 (1) ◽  
pp. 1-15
Author(s):  
C. F. Asenjo ◽  
D. H. Cook ◽  
M. del C. De Fernández ◽  
L. A. Alvarez
Keyword(s):  
Special Reference ◽  
Proteolytic Activity ◽  
Maximum Activity ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Fruit Pulp ◽  
Hydrogen Ion Concentration ◽  
Milk Clotting ◽  
Green Fruit ◽  
Milk Clotting Activity

1. All parts of the papaya plant, with the exception of the seed, showed varying degrees of proteolytic activity. 2. Milk clotting activity appeared first in the leaf and later, in the stem and root. 3. The largest amount of proteolytic activity was concentrated in the green fruit rind and, in decreasing quantities, in the leaf, fruit pulp, stem, and root. 4. In the leaf and, to a lesser extent, in the stem and root, a definite variation took place in proteolytic activity during the thirteen initial months of growth. Maximum activity was reached between the fourth and ninth months. 5. Data have been collected regarding the moisture, hydrogen ion concentration, and nitrogen content of the various parts of the papaya plant during its initial thirteen months of growth.

scholarly journals Studies in the mechanism of enzyme action. I.—Rôle of the reaction of the medium in fixing the optimum temperature of a ferment

1921 ◽  
Vol 92 (642) ◽  
pp. 1-6 ◽  
Keyword(s):  
Enzyme Activity ◽  
Temperature Effect ◽  
Acid Medium ◽  
Hydrogen Ion ◽  
Ion Concentration ◽  
Optimum Temperature ◽  
Hydrogen Ion Concentration ◽  
Enzyme Action

Previously, it has been shown for the enzyme maltase —enzyme requiring an acid medium in which to act to best advantage—that increase in the acidity or hydrogen ion concentration of the medium in which the enzyme acts, beyond the optimum acidity, leads to a fall of optimum temperature. The mechanism of his temperature of this temperature effect appears clearly to be due to a certain disablement of the enzyme activity, estimated at the optimum temperature point; which decrease of activity is itself a function of the degree of acidity of the medium in excess of that necessary to produce optimum activation. Being in this way a disablement effect, the question arises whether, by adding to the quantity of enzyme in action, the lowering of optimum temperature which takes place can be controlled. To answer that question, the experiments described in the present paper were undertaken. For the investigation, the enzyme used is the maltase of Aspergillus oryzœ , the same preparation being employed as studied by us in two previous communications, a specially active specimen of takadiastase, purified by repeated solution in water and reprecipitation by alcohol.

scholarly journals HYDROGEN ION CONCENTRATION OF CULTURES OF PNEUMOCOCCI OF THE DIFFERENT TYPES IN CARBOHYDRATE MEDIA

1919 ◽  
Vol 30 (4) ◽  
pp. 359-378 ◽  
Author(s):  
O. T. Avery ◽  
Glenn E. Cullen
Keyword(s):  
Hydrogen Ion ◽  
Ion Concentration ◽  
Hydrogen Ion Concentration ◽  
Rate Of Reaction ◽  
Different Types ◽  
Optimum Reaction ◽  
Reaction Change

1. The optimum hydrogen ion concentration for growth of pneumococcus is pH 7.8. 2. In broth cultures growth of pneumococcus continues until a final hydrogen ion concentration of about pH 5.0 is reached, if sufficient fermentable carbohydrate' (above 0.4 per cent) is present. Apparently this acidity is sufficient in itself to stop growth. 3. If less carbohydrate is present in the medium growth ceases at a lower hydrogen ion concentration, apparently because of exhaustion of carbohydrate. If no carbohydrate is present save that extracted from the meat of which the broth is made (plain broth medium), growth initiated at pH 7.8 (optimum reaction) ceases at about pH 7.0. 4. If bacteria-free filtrates of plain broth cultures in which growth has ceased are readjusted to pH 7.8 and reinoculated with pneumococcus, no growth occurs unless carbohydrate is added. However, if bacteria-free filtrates of dextrose broth cultures in which growth has ceased (pH 5) are readjusted to pH 7.8 and reinoculated with pneumococcus growth occurs. 5. Cultures of pneumococcus with all the carbohydrates which were fermentable under the conditions used, namely maltose, saccharose, lactose, galactose, raffinose, dextrose, and inulin, gave identical results in the rate of reaction change, and final hydrogen ion concentration (pH 5.0) attained. 6. The different immunological types of pneumococcus, for the limited number of strains studied, behaved alike in fermenting the carbohydrates mentioned above.

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