Fluorescence quenched quinone methide based activity probes--a cautionary tale.

A carbamate linked quenching group coupled with a pro-quinone methide reactive core provides an effective tool for studying enzyme function without problems associated with background fluorescence from unreacted probe. However, the relatively slow fragmentation of the carbamate linkage in such a strategy may cause problems of loss of signal or a decoupling of enzyme activity and labelling.

BODIPY probes to study peroxisome dynamics in vivo.

There is a continuing need for bioprobes that are target-specific and combine speed of delivery with maintenance of normal cell behaviour. Towards this end, we are developing small pro-fluorescent molecules that provide such specificity through chemical activation by biomolecules. We have generated a set of BODIPY (boron dipyrromethane) fluorophores, including one that is intrinsically non-fluorescent but on incubation with cells becomes fluorescent at its target site.

Structure activity studies with xenobiotic substrates using carboxylesterases isolated from Arabidopsis thaliana.

Carboxylesterases (CXEs) catalyse the hydrolysis of xenobiotics and natural products radically altering their biological activities. Whereas the substrate selectivity of animal CXEs, such as porcine liver esterase (PLE) have been well studied, the respective enzymes in plants have yet to be defined and their activities determined. Using Arabidopsis thaliana (At) as a source, five representative members of the alpha/beta hydrolase AtCXE family of proteins have been cloned, expressed and the purified recombinant proteins assayed for esterase activity with xenobiotic substrates.