Degradation of Aspartate Transcarbamylase in Growing and Starved Bacillus Subtilis Cells

Aspartate transcarbamylase (ATCase) is degraded upon starvation of Bacillus subtilis cells for carbon or nitrogen. The rate of ATCase degradation in exponentially growing B. subtilis cells was determined by measurement of enzyme activity after the addition of uridine to repress further enzyme synthesis and by specific immunoprecipitation of the enzyme from cells grown in the presence of (('3)H)leucine. ATCase was degraded with a half-life of about 1.5h in cells growing on a glucose-salts minimal medium with NH(,4)('+) ions as the sole source of nitrogen. Replacement of NH(,4)('+) in this medium with a combination of the amino acids aspartate, glutamate, isoleucine, proline, and threonine reduced the degradation rate to an undetectable level. Various other amino acids had smaller effects on the rate of degradation. The carbon source also influenced the degradation rate, but to a smaller extent than the nitrogen source. The effects of these nutritional variables on the rate of bulk protein turnover in growing cells were generally similar to their effects on degradation of ATCase.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biochemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2014

Author dc:creator

• Bond, Richard William

• Chemistry, Biochemistry

Identifier

(UMI)AAI8502074

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/70536