TY - JOUR
TI - Selectivity of commonly used pharmacological inhibitors for cystathionine β synthase (CBS) and cystathionine γ lyase (CSE)
AU - Asimakopoulou, A.
AU - Panopoulos, P.
AU - Chasapis, C.T.
AU - Coletta, C.
AU - Zhou, Z.
AU - Cirino, G.
AU - Giannis, A.
AU - Szabo, C.
AU - Spyroulias, G.A.
AU - Papapetropoulos, A.
JO - British Journal of Pharmacology
PY - 2013
VL - 169
TODO - 4
SP - 922-932
PB - 
SN - 0007-1188, 1476-5381
TODO - 10.1111/bph.12171
TODO - aminoethoxyvinylglycine;  aminooxyacetic acid;  cyanoalanine;  cystathionine beta synthase inhibitor;  cystathionine gamma lyase inhibitor;  cysteine;  glutathione transferase;  hybrid protein;  hydrogen sulfide;  hydroxylamine;  lyase inhibitor;  methylene blue;  nitric oxide;  propargylglycine;  trifluoroalanine;  unclassified drug, animal tissue;  article;  concentration response;  controlled study;  drug potency;  drug selectivity;  drug specificity;  enzyme activity;  enzyme analysis;  enzyme inhibition;  enzyme inhibitor interaction;  enzyme purification;  Escherichia coli;  human;  IC 50;  nonhuman;  priority journal;  protein expression;  rat;  vascular ring, Alanine;  Alkynes;  Animals;  Aorta, Thoracic;  Cystathionine beta-Synthase;  Cystathionine gamma-Lyase;  Enzyme Inhibitors;  Glutathione Transferase;  Glycine;  Humans;  Hydrogen Sulfide;  Kinetics;  Nitric Oxide;  Nitric Oxide Donors;  Peptide Fragments;  Rats;  Rats, Sprague-Dawley;  Recombinant Fusion Proteins;  Vasodilation
TODO - Background and Purpose: Hydrogen sulfide (H2S) is a signalling molecule that belongs to the gasotransmitter family. Two major sources for endogenous enzymatic production of H2S are cystathionine β synthase (CBS) and cystathionine γ lyase (CSE). In the present study, we examined the selectivity of commonly used pharmacological inhibitors of H 2S biosynthesis towards CSE and CBS. Experimental Approach: To address this question, human CSE or CBS enzymes were expressed and purified from Escherichia coli as fusion proteins with GSH-S-transferase. After purification, the activity of the recombinant enzymes was tested using the methylene blue method. Key Results: β-cyanoalanine (BCA) was more potent in inhibiting CSE than propargylglycine (PAG) (IC50 14 ± 0.2 μM vs. 40 ± 8 μM respectively). Similar to PAG, L-aminoethoxyvinylglycine (AVG) only inhibited CSE, but did so at much lower concentrations. On the other hand, aminooxyacetic acid (AOAA), a frequently used CBS inhibitor, was more potent in inhibiting CSE compared with BCA and PAG (IC50 1.1 ± 0.1 μM); the IC50 for AOAA for inhibiting CBS was 8.5 ± 0.7 μM. In line with our biochemical observations, relaxation to L-cysteine was blocked by AOAA in aortic rings that lacked CBS expression. Trifluoroalanine and hydroxylamine, two compounds that have also been used to block H2S biosynthesis, blocked the activity of CBS and CSE. Trifluoroalanine had a fourfold lower IC50 for CBS versus CSE, while hydroxylamine was 60-fold more selective against CSE. Conclusions and Implications: In conclusion, although PAG, AVG and BCA exhibit selectivity in inhibiting CSE versus CBS, no selective pharmacological CBS inhibitor is currently available. © 2012 The British Pharmacological Society.
ER -