Biacore Ab

Pharmacia Biosensor Ab

Stefan Lofangs

Robert Karlsson

Inger Ronnberg

Ralf W Glaser

Katarina Lagerstrom

Methods and kits are disclosed for detecting betalactam-containing compounds in a sample, and typically liquid products intended for human consumption such as milk. Betalactam-containing compounds include the class of betalactam antibiotics which may be present as undesired contaminates of milk. The methods involves contacting the sample with a D,D-carboxypeptidase and a substrate having a carboxyterminal D-alanine-D-alanine to form a reaction mixture, wherein the D,D-carboxypeptidase is capable of cleaving the terminal D-alanine from the substrate to yield a cleaved substrate. In an optional step, the reaction mixture is further contacted with a ligand specific to the cleaved substrate or substrate. The cleaved substrate or substrate of the reaction mixture, or the ligand specific to the cleaved substrate or substrate, is then captured by a surface-bound binding partner, with the amount of captured material being indicative to the amount of betalactam-containing compound in the sample. Kits for performing the methods of this invention are also disclosed.

Method and kit for detecting betalactam-containing compounds

Method of determining affinity or kinetic properties in solution

Method of producing bilayer lipid membranes

Solid phase binding assay

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Uppsala, Sweden

Stefan Lofangs