Turnover of abnormal proteins inBacillus megateriumandSaccharomyces cerevisiae: differences between in vivo and in vitro degradation

✍ Scribed by Ashok Kumar Chopra; Marie Strnadová; Jiří Chaloupka

• Book ID: 104764029
• Publisher: Springer
• Year: 1986
• Tongue: English
• Weight: 718 KB
• Volume: 145
• Category: Article
• ISSN: 0302-8933
• DOI: 10.1007/bf00413034

✦ Synopsis

Degradation of abnormal proteins in Bacillus megaterium and Saccharomyces cerevisiae in vivo was compared with that in cell-free extracts. Protein degradation in vivo, when the cells were labelled with a4C-leucine during growth in the presence of ethionine, was affected by the concentration of the analogue used. Proteins synthesized in the presence of 0.2-1 mM ethionine were degraded most rapidly in both organisms. The proteolytic enzyme system of yeast degraded the analogue-containing proteins in vitro faster than the normal proteins. This holds also for proteins synthesized in the presence of 5 mM ethionine, whose degradation in vivo was impaired. The proteolytic system of B. megaterium, on the other hand, was unable in vitro to differentiate between normal and abnormal proteins. Denatured proteins underwent preferential degradation over normal and ethionine-containing proteins.