Brancaleone V et al. 2016; D-penicillamine modulates hydrogen sulfide (H2S) pathway through selective inhibition of cystathionine-gamma-lyase (CSE); Br. J. Pharmacol. 173(9):1556-65

Study design: D-penicillamine (D-pen) was tested on mouse artoa rings for its vasodilatory effect as a possible cysteine analogue and its effect on H2S biosynthesis.

Results: No vasodilatory effect was observed. D-pen did not function as a substrate to replace L-cysteine, but it reduced L-cysteine-induced vasodilatation by inhibiting H2S biosynthesis. CSE was inhibited selectively by D-pen in pyridoxal-5‘-phosphate-dependent manner.

Conclusions: Results indicate that D-pen could act as a selective CSE inhibitor accounting for a beneficial effect of D-pen in rheumatoid arthritis patients, where H2S has proved to be harmful.