منابع مشابه
Studies on Crystalline Urease
1. Crystalline urease is not inactivated by trypsin in the absence of a gum. In fact, the presence of trypsin alone in aqueous solutions of urease has an action similar to that of gum, that is, it acts as a "protective colloid" for urease. 2. Crystalline urease is inactivated by trypsin in the presence of a gum. This occurs with great rapidity if purified (crystalline) trypsin is used. 3. If tr...
متن کاملTemperature Activation of the Urease-urea System Using Crude and Crystalline Urease
1. The hydrolysis of urea catalyzed by jack bean meal has been followed by determining colorimetrically after Nesslerization the ammonia nitrogen, and volumetrically the carbon dioxide liberated at successive intervals during the reaction. During the early part of hydrolysis the rate of ammonia or carbon dioxide liberation is constant for all the urease solutions which were used. 2. When log ra...
متن کاملActivation of the Urease - Urea System Using Crude and Crystalline
Many studies of the kinetics of enzyme action as a function of temperature have been made. The older work (for reference cf. Haldane, 1930; Tauber, 1937) indicates that while the velocity of an enzyme-catalyzed reaction increases with rise in temperature, up to the inactivation temperature of the enzyme, this change in rate is not an exponential function of the absolute temperature. I t has bee...
متن کاملUrease. Part II. The Mechanism of the Zymolysis of Urea.
Since this paper was submitted for publication, a paper has appeared on the mechanism of urease by Mack and Villars [1923]. In this paper the authors agree with the present writer in accepting the Werner formula for urea. They have detected and estimated cyanate in solutions of urea undergoing zymolysis, and also have shown that the cyanate rises to a maximum and falls again towards the end of ...
متن کاملThe Activity of Crystalline Urease as a Function of Oxidation-reduction Potential*
A number of different enzymes are activated by certain reducing agents (e.g., KCN, H&S, cysteine, and reduced glutathione) and inactivated by oxidizing agents (e.g., K3Fe(CN)&, HzOz, and cystine). Under ideal conditions such inactivation is reversible by the addition of reducing agents (for a review of this subject cJ Hellerman (1937, 1939)). These results have been interpreted on the basis of ...
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ژورنال
عنوان ژورنال: Journal of Biological Chemistry
سال: 1928
ISSN: 0021-9258
DOI: 10.1016/s0021-9258(18)84116-3