The effect of 4-aminopyridine (4-AP) on Kv channel activation has been extensively investigated, but its interaction with inactivation is less well understood. Voltage-clamp fluorimetry was used to directly monitor the action of 4-AP on conformational changes associated with slow inactivation of Shaker channels. Tetramethylrhodamine-5-maleimide was used to fluorescently label substituted cystei...

General Aspects Determination of characteristic fluorescence parameters i.e. spectral properties, quantum yields, polarizations, and lifetimes, is important in the study of excited states of atoms, molecules, and crystals and also for diagnostic purposes in the physical, chemical, biological, and medical sciences. The appeal of fluorescence methodologies lies in their intrinsic sensitivity and ...

Pulsed-light time-resolved fluorometry of lanthanide chelates has proved to be very sensitive for use with nonisotopic immunoassays. We describe a manually operated fluorometer with a conventional xenon flashtube. Sensitivity for 1-s determinations is similar to that of radioisotopic methods.

A screening assay to test the inducing capacity of macrolides by fusing the attenuator of the inducible erm(B) gene from Streptococcus pneumoniae HM28 with the gfpmut1 gene has been designed. Fluorescence was detected under UV light around disks impregnated with inducer macrolides (erythromycin or azithromycin) but not with noninducer ketolides. Induction could be quantified by fluorometry.