Related Experiment Video
Updated: Jun 27, 2026

Hot Biological Catalysis: Isothermal Titration Calorimetry to Characterize Enzymatic Reactions
Published on: April 4, 2014
Denaturation of Bacillus amyloliquefaciens alpha-amylase with urea
B Shareghi1, M Arabi, M Zargham
1Department of Biology, Faculty of Basic Sciences, Shahrekord University, Iran
Abstract:
The urea induced denaturation of the Bacillus amyoliqefaciens alpha-amylase (E.C. 3.2.1.1) was studied by absorption measurements in the near ultra-violet region and specific activity measurements. Spectral measurements were made at pH 6.9 and over the temperature range 20-80 degrees C. It has been observed that urea induced a cooperative transition. In the absence of denaturant, the Gibs energy changes were in the range of 8-15 kcal mol(-1). alpha-amylase lost 80% of its activity in the concentrated solution of urea. alpha-amylase was more thermostable than other mesophilic enzymes.
Related Concept Videos
Protein Denaturation
Amides to Carboxylic Acids: Hydrolysis
Acid-catalyzed hydrolysis:
Hydrolysis of amides under acidic conditions yields carboxylic acids. Since the reaction occurs slowly, hydrolysis requires the conditions of heat.
The mechanism begins with the protonation of the carbonyl oxygen by the acid catalyst. The protonation makes the amide carbonyl carbon more...
Acid Halides to Amides: Aminolysis
In the first step of the aminolysis mechanism, the amine attacks the carbonyl carbon of the acyl chloride to form a tetrahedral intermediate. In the second step, the carbonyl group is re-formed with the elimination of a chloride...
Basicity of Aliphatic Amines
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Aldehydes and Ketones with Amines: Enamine Formation Mechanism
Amino Acid Catabolism

