Top ▲

Hydrogen sulphide synthesis C

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).


Click here for help

« Hide

Hydrogen sulfide is a gasotransmitter, with similarities to nitric oxide and carbon monoxide. Although the enzymes indicated below have multiple enzymatic activities, the focus here is the generation of hydrogen sulphide (H2S) and the enzymatic characteristics are described accordingly. Cystathionine β-synthase (CBS) and cystathionine γ-lyase (CSE) are pyridoxal phosphate (PLP)-dependent enzymes. 3-mercaptopyruvate sulfurtransferase (3-MPST) functions to generate H2S; only CAT is PLP-dependent, while 3-MPST is not. Thus, this third pathway is sometimes referred to as PLP-independent. CBS and CSE are predominantly cytosolic enzymes, while 3-MPST is found both in the cytosol and the mitochondria. For an authoritative review on the pharmacological modulation of H2S levels, see Szabo and Papapetropoulos, 2017 [7].


Click here for help

CBS (Cystathionine β-synthase) C Show summary »

Target Id 1443
Nomenclature Cystathionine β-synthase
Common abbreviation CBS
Previous and unofficial names Serine sulfhydrase | beta-thionase | hemoprotein H-450 | HIP4
Genes CBS (Hs), Cbs (Mm), Cbs (Rn)
Ensembl ID ENSG00000160200 (Hs), ENSMUSG00000024039 (Mm), ENSRNOG00000029528 (Rn)
UniProtKB AC P35520 (Hs), Q91WT9 (Mm), P32232 (Rn)
EC number
Endogenous substrates
L-homocysteine [2]
L-cysteine pKm 2.2 [2]
pyridoxal 5-phosphate
aminooxyacetic acid pIC50 5.1 [1]
benserazide pIC50 ~4.5 [4]
Comment A copper-containing metabolite of disulfiram acts as a direct inhibitor of CBS and H2S scavenger [8].

CSE (Cystathionine γ-lyase) C Show summary »

CAT (L-Cysteine:2-oxoglutarate aminotransferase) C Show summary »

MPST (3-Mercaptopyruvate sulfurtransferase) C Show summary »

Further reading

Click here for help

Show »


Click here for help

Show »

NC-IUPHAR subcommittee and family contributors

Show »

How to cite this family page

Database page citation (select format):

Concise Guide to PHARMACOLOGY citation:

Alexander SP, Fabbro D, Kelly E, Mathie A, Peters JA, Veale EL et al. (2021) THE CONCISE GUIDE TO PHARMACOLOGY 2021/22: Enzymes. Br J Pharmacol. 178 Suppl 1:S313-S411.