Figure 3.
Modulation of cGMP by HO-2. HEK-293 cells were transfected with cDNAs encoding either pCMV-mycHO-2 or parent vector. (A) Expression of pCMV-mycHO-2 was assessed by immunoblotting. (B) Activity was determined by measuring the conversion of [3H]iron mesoporphyrin into [3H]bilirubin. In A, the band at 64 kDa is an endogenous protein that is recognized by the anti-myc antibody; the band slightly >36 kDa is myc-tagged HO-2. (C) Increasing concentrations of HO-2 (1–25 μg) were transfected, and cGMP levels were determined. (D) Effects of inhibitors of HO and guanylyl cyclase on cGMP levels in cells transfected with 10 μg DNA. SE ranged between 7 and 15 pmol of cGMP/mg protein.