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Repression der Ureasebiosynthese in Neurospora crassa durch Ammoniumionen

✍ Scribed by A. Schluttig; W. Fritsche

Publisher
John Wiley and Sons
Year
2007
Tongue
English
Weight
345 KB
Volume
15
Category
Article
ISSN
0233-111X

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✦ Synopsis

Abstract

The regulation of the synthesis of the enzyme urease (urea amido hydrolase E.C. 3.5.1.5.) in Neurospora crassa was investigated. The biosynthesis of urease is repressed by ammonium ions. Under ammonium excess conditions the specific activity of urease decreases from 0.980 to 0.180 μmoles NH~3~/min/mg protein.

By addition of cycloheximide it was shown that ammonia influences the synthesis of this enzyme. Enzyme induction by the substrate could be excluded.

Even under the conditions of highest repression a specific activity of urease of 0.180 μmoles NH~3~/min/mg protein was measured. Possible causes of this constitutive enzyme level are discussed.

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