Aspergillus oryzae acetamidase catalyzes degradation of ethyl carbamate
Kazuo Masaki1, Kanako Fujihara2, Dararat Kakizono3
1National Research Institute of Brewing, 3-7-1 Kagamiyama, Higashihiroshima 739-0046, Japan; Graduate School of Biosphere Science, Hiroshima University, 1-4-4 Kagamiyama, Higashihiroshima 739-8528, Japan.
Abstract:
Urethanase (EC 3.5.1.75) catalyzes the hydrolysis of ethyl carbamate (EC) to ethanol, carbon dioxide, and ammonia. From our recent study, we expected that an acetamidase encoded by amdS of Aspergillus oryzae may catalyze the degradation of EC because it is homologous with a Candida parapsilosis urethanase (CPUTNase) recently identified. Urethanase is a prospective candidate to reduce EC in alcoholic beverages, but knowledge of this enzyme is very limited. Recombinant AmdS was expressed to study its enzymatic properties. Purified AmdS was identified as a homo-tetramer consisting of four 60 kDa units and exhibited urethanase activity. In a 20% ethanol solution, AmdS had 65% activity compared with a solution without ethanol. Residual activity after 18 h indicated that AmdS was stable in 0%-40% ethanol solutions. The optimum temperature of AmdS was 40 °C. This enzyme showed urethanase activity at pH 6.4-9.6 and exhibited its highest activity at pH 9.6. The Km value of AmdS for EC was 8.2 mM, similar to the Km value (7.6 mM) of CPUTNase. AmdS showed activity not only for EC and acetamide but also other amide compounds. In this study, we investigated the enzymatic properties of AmdS that was identified as acetamidase and showed that an amidase can be an enzymatic candidate that degrades EC.
More Related Videos
09:25Genome-wide Analysis of Histone Modifications Distribution using the Chromatin Immunoprecipitation Sequencing Method in Magnaporthe oryzae
Published on: June 2, 2021
06:46Facile Preparation of 2Z,4E-Dienamides by the Olefination of Electron-deficient Alkenes with Allyl Acetate
Published on: June 21, 2017
Related Concept Videos
Alkylation of β-Ketoester Enolates: Acetoacetic Ester Synthesis
Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Amino Acid Catabolism
Amines to Amides: Acylation of Amines
Next, the second equivalent of amine serves as a Brønsted base and deprotonates the quaternary...
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...
Preparation of 1° Amines: Hofmann and Curtius Rearrangement Mechanism
