Effects of 100 µM NS 2028 on fluorescence intensity of FlAsH labelled haem- free TC4-Y135A/R139A sGC (A) and ReAsH labelled TC4-WT sGC (B) after 90 min incubation.

cGMP reporter cells were cotransfected with WT α1 sGC and the respective β1 sGC and labelled with FlAsH or ReAsH. Fluorescence intensity of single cells was monitored in a time series of 120 laser scans and is expressed as % of start value which was obtained before application of the test compounds. Data are means ± S.E.M. from 3–5 single cells assayed on different days.