[H.sub.2]S is produced by cystathionine [beta]-synthase, cystathionine [gamma]-lyase, L-cysteine desulfhydrase
, and 3-mercaptopyruvate sulfurtransferase (for an overview see  and references within).
In plants, [H.sub.2]S is mainly produced via the L-/D-cysteine desulfhydrase enzymes (LCD/ DCD) and it has been reported to be involved in stress responses to drought, heat, heavy metal and salt during seed germination and seedling growth (ZHANG et al., 2010a; JIN et al., 2011; LAI et al., 2014; LI et al., 2014).
Endogenous [H.sub.2]S content determination and L-/D-cysteine desulfhydrase activity assay
The [Pb.sup.2+] could combine with the glycoproteins of cell walls, and then was transmitted into cytoplasm which contained [S.sup.2-] generated by assimilation of sulfate reduction and the effect of cysteine desulfhydrase
, and then synthesized PbS precipitation with [S.sup.2-] in the cytoplasm, eventually moved out of the cell (11).
(2005) Isolation and characterization of a D-cysteine desulfhydrase
protein from Arabidopsis thaliana.
Then, cysteine produced [S.sup.2-] by a cysteine desulfhydrase
in presence of zinc.
Role of D-Cysteine Desulfhydrase
in the adaptation of Escherichia coli to D-Cysteine.
Gotor, "An O- Acetylserine(thiol)lyase homolog with l-Cysteine desulfhydrase
activity regulates cysteine homeostasis in arabidopsis," Plant Physiology, vol.