Fig. 1.

CBS and CSE: activity, Western blot analysis, and qRT-PCR of human penile tissue. (A) HCC-expressed mRNA for both CBS and CSE as determined by qRT-PCR. (B) Representative Western blot analysis for CBS and CSE. (C) HCC homogenate produced H₂S under basal conditions (open bar). Incubation of HCC homogenate with 10 mM l-Cys caused a significant increase in the H₂S production compared with basal values (**, P < 0.001). PAG (10 mM), 1 mM AOAA, or 10 mM PAG plus 1 mM AOAA significantly inhibited the l-Cys-induced increase in H₂S production (†, P < 0.01). Data represent the mean ± SEM from 3 or 4 different human specimens.