title: Intracellular protein degradation in Neurospora crassa.
abstract: In exponentially growing cultures of Neurospora crassa, the basal rate of protein degradation increases as the constant of the rate of growth decreases, so that in slow growing cells (mu = 0.13) the rate of protein degradation is about 25% of the rate of protein accumulation. During glucose starvation and shift-down transition of growth, the rate of protein degradation is greatly enhanced, and a moderate reduction (about 30%) of the ATP level is observed. Treatment of glucose-starved cells with 2-deoxyglucose reduces the ATP content by 70% and blocks protein degradation. The addition of cycloheximide, given at the onset of glucose starvation, prevents the enhancement of protein degradation; instead cycloheximide is without effect if added when proteolysis has already started. At a supraoptimal temperature (42 degrees C) the basal rate of protein degradation is not stimulated, contrary to the behavior observed in bacteria. Guanosine nucleotides, which appear to have a regulatory role for protein degradation in bacteria, are not found in N. crassa.
mesh_terms: D000596:Amino Acids / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D003847:Deoxyglucose / Q000494:pharmacology; D005656:Fungal Proteins / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D007700:Kinetics; D008757:Methylglucosides / Q000494:pharmacology; D009491:Neurospora / Q000378:metabolism*; D009492:Neurospora crassa / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism*
chemical_list: D000596:Amino Acids; D005656:Fungal Proteins; D008757:Methylglucosides; D003513:Cycloheximide; D003847:Deoxyglucose; D010447:Peptide Hydrolases; D005947:Glucose