The relative release of alkaline phosphatase and beta-galactosidase of E. coli C29, in exponential and stationary phases, through different lysis methods

Abstract

Alkaline phosphatase (AP) in Escherichia coli C29 is constitutively expressed, unlike wild type E. coli in which AP expression has to be induced. However, it has been observed that AP activities drop upon entry into stationary phase. In contrast, another study demonstrated an increase in AP levels in stationary phase. It is speculated that ineffective bead bashing lysis of stationary cells resulted in an underestimation of total protein and thus overestimation of AP specific activity. The aim of this study was to confirm this hypothesis by investigating the lysis efficiency of bead-bashing and chemical whole cell lysis on the release of AP and β -galactosidase ( β -gal), a cytoplasmic protein. AP levels were also investigated throughout exponential and stationary phase. The AP/ β -gal ratio confirmed the incomplete lysis of the bead bashing method, and that AP levels decreased upon transition into stationary phase, but a subsequent substantial increase in the ratio needs further investigation.