The heat, ultraviolet and rihoflavin-sensitized visible inactivations of taka-amylase A are strongly inhibited by the presence of its substrate. The stabilization of the secondary structure of enzyme protein by the conformation change due to the formation of enzyme-substrate and -product complexes is responsible for the protection of enzyme from the heat inactivation. The photoinactivations are...

Heat inactivation characteristics differed for acidic (A), neutral (N), and basic (B) broccoli peroxidase. At 65 degrees C, A was the most heat stable followed by N and B. The activation energies for denaturation were 388, 189, and 269 kJ/mol for A, N, and B, respectively. Reactivation of N occurred rapidly, within 10 min after the heated enzyme was cooled and incubated at room temperature. The...

The heat, ultraviolet and rihoflavin-sensitized visible inactivations of taka-amylase A are strongly inhibited by the presence of its substrate. The stabilization of the secondary structure of enzyme protein by the conformation change due to the formation of enzyme-substrate and -product complexes is responsible for the protection of enzyme from the heat inactivation. The photoinactivations are...

Adsorption and heat inactivation studies were made on a series of host range, turbid (ht) mutants of coliphage T2H to determine the mechanisms of phenotypic expression of these genes and of the additivity of gene effects. The ht mutants adsorb to the resistant cell B/2H at a slower rate than the clear h mutant; double and triple ht mutants adsorb with increased efficiency. Some mutants show inc...

The effect of raw and anaerobically digested sludge on heat inactivation of poliovirus was investigated. Raw sludge was found to be very protective of poliovirus plaque-forming ability at all temperatures studied, but digested sludge had variable effects that were highly dependent upon the experimental conditions. In low concentrations and at relatively low inactivation temperatures, digested s...

Early work on bacteriophage included several studies of the effect of heat on the lytic principle. For example, d'Herelle (1) found Shiga bacteriophage survived exposure to 65°C. for 1⁄2 hour. Kabeshima (2) working with the same phage observed activity after 1⁄2 hour at 70°C. and set the inactivation temperature at 75°C. , using a like period of exposure. Others, particularly Weinberg and Aznar...

IN a recent series of publications Northrop [1930, 1, 2; 1931] has advanced very strong evidence that pepsin is a protein. Starting from commercial pepsin, by suitably regulating the pH and precipitating with the aid of magnesium or ammonium sulphate a crystalline product was obtained which had the general properties of a protein. In particular, solutions of this crystalline pepsin were coagula...