title: Stability of protein and ribonucleic acid in Bacillus stearothermophilus.
abstract: The turnover of protein in a prototrophic strain of Bacillus stearothermophilus during exponential growth in a salts medium with glucose or succinate as carbon source was about 4 %/h and in a richer nutrient broth medium about 23 %/h. Protein degradation under non-growing conditions conformed to a similar pattern. The turnover of RNA (non-messenger) was about 1 %/h in salts medium and about 9 %/h in nutrient broth. The turnover of protein and RNA in the thermophile is thus moderate rather than massive. This conclusion was confirmed by measurement of the decay of a specific enzyme, isocitrate lyase, in the prototroph and of the overall protein turnover in a non-prototrophic strain of B. stearothermophilus. The half-lives of a number of enzyme systems in intact cells of the prototrophic thermophile at its optimum growth temperature showed some variation but indicated a significant rate of inactivation. Such decay of protein in vivo apparently accounts for the moderate protein turnover observed during growth.
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism*; D002474:Cell-Free System; D001411:Geobacillus stearothermophilus / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism; D007521:Isocitrate Dehydrogenase / Q000378:metabolism; D007523:Isocitrates; D008291:Malate Dehydrogenase / Q000378:metabolism; D007652:Oxo-Acid-Lyases / Q000378:metabolism; D011766:Pyruvate Carboxylase / Q000378:metabolism; D011770:Pyruvate Kinase / Q000378:metabolism; D012329:RNA, Bacterial / Q000378:metabolism*; D013386:Succinates / Q000378:metabolism; D013696:Temperature
chemical_list: D001426:Bacterial Proteins; D007523:Isocitrates; D012329:RNA, Bacterial; D013386:Succinates; D008291:Malate Dehydrogenase; D007521:Isocitrate Dehydrogenase; D011770:Pyruvate Kinase; D007652:Oxo-Acid-Lyases; D011766:Pyruvate Carboxylase; D005947:Glucose