Biochemical and Enzyme Kinetic Applications for the Characterization of βLactamases

For the last 20 yr thin-layer polyacrylamide isoelectric focusing (IEF) has played a major role in the identification and characterization of β-lactamases. IEF is able to distinguish enzymes that focus only 0.05 pI apart (1 ), but the exponential increase rin the numbers of β-lactamases discovered over the last 10 yr has meant that this method no longer provides sufficient resolution to distinguish the majority of β-lactamases. Today the pI of a β-lactamase is still an essential determinant that must be used in combination with a variety of other data. Moreover, the IEF of β-lactamases is now entering a new era as this technique can be adapted to provide important biochemical information on β-lactamases other than simply their pI values. These approaches are discussed in Subheading 3.1.