title: Protein turnover in the extreme thermophile Thermus aquaticus.
abstract: Protein turnover in the extreme bacterial thermophile Thermus aquaticus was examined in exponential cultures at 75 degrees C. The relative amount of [3H]leucine incorporated into trichloroacetic acid-insoluble material was stable in pulse-chase experiments assayed over 2.5 h. The trichloroacetic acid-insoluble radioactive leucine was stable upon the addition of chloramphenicol, which blocks protein synthesis in T. aquaticus. The specific activity of a phosphate-repressible alkaline phosphatase, investigated in the presence of chloramphenicol, did not decrease. The addition of excess orthophosphate to cultures derepressed for the alkaline phosphatase did not show a marked effect on the specific activity over a 2-h period. On the basis of these four experiments, it does not appear that a high protein turnover rate is essential for the thermophily of T. aquaticus at 75 degrees C.
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism*; D002701:Chloramphenicol / Q000494:pharmacology; D006358:Hot Temperature; D007700:Kinetics; D013824:Thermus / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; D002701:Chloramphenicol; D000469:Alkaline Phosphatase