DnaK ATPase activity revisited.
It has recently been reported that the ATPase activity of DnaK, a 70 kDa heat shock protein from E. coli, is autostimulated by increasing protein concentration [(1993) FEBS Lett. 322, 277-279], suggesting that the DnaK dimer may be the enzymatically active species. In this paper we investigated the ATPase activity of different DnaK preparations; we found that the turnover number was very dependent on protein purification. With HPLC-purified DnaK we found a turnover number 20- to 50-fold lower than typical values previously published and no evidence of autostimulation, indicating that the monomer is the active species.
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Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064.
Reid
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Shi
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Fink
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D000251:Adenosine Triphosphatases / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D004926:Escherichia coli / Q000378:metabolism; D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins / Q000302:isolation & purification / Q000378:metabolism*
D029968:Escherichia coli Proteins; D018840:HSP70 Heat-Shock Proteins; D006360:Heat-Shock Proteins; D000251:Adenosine Triphosphatases; C063842:dnaK protein, E coli