Figure 2 | Scientific Reports

Figure 2

From: Detection of carbapenemase producing enterobacteria using an ion sensitive field effect transistor sensor

Figure 2Figure 2

ISFET measurements using various quantities of MβL (a) and serine reactive (SbL) carbapenemase (b) containing crude protein extracts. The enzyme concentration in each preparation was estimated through spectrophotometric measurement of imipenem hydrolysis and the Michaelis–Menten equation using the published steady-state constants. Graphs of the actual measurements, of relative voltage changes and of control corrected curves are shown. For the linear phase of each corrected curve the rate of voltage change was determined and plotted against the enzyme quantity (lower graphs). The detection threshold was set to − 0.33 mV/min and the enzyme concentration required to reach this limit was estimated through linear regression.

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