Characterization of the enzymic capacity for cysteine desulphhydration in liver and kidney of the rat

Biochem J. 1982 Aug 15;206(2):267-77. doi: 10.1042/bj2060267.

Abstract

The contribution of cystathionine gamma-lyase, cystathionine beta-synthase and cysteine aminotransferase coupled to 3-mercaptopyruvate sulphurtransferase to cysteine desulphhydration in rat liver and kidney was assessed with four different assay systems. Cystathionine gamma-lyase and cystathionine beta-synthase were active when homogenates were incubated with 280 mM-L-cysteine and 3 mM-pyridoxal 5'-phosphate at pH 7.8. Cysteine aminotransferase in combination with 3-mercaptopyruvate sulphurtransferase catalysed essentially all of the H2S production from cysteine at pH 9.7 with 160 mM-L-cysteine, 2 mM-pyridoxal 5'-phosphate, 3 mM-2-oxoglutarate and 3 mM-dithiothreitol. At more-physiological concentrations of cysteine (2 mM) cystathionine gamma-lyase and cystathionine beta-synthase both appeared to be active in cysteine desulphhydration, whereas the aminotransferase pathway did not. The effect of inhibition of cystathionine gamma-lyase by a suicide inactivator, propargylglycine, in the intact rat was also investigated; there was no significant effect of propargylglycine administration on the urinary excretion of total 35S, 35SO4(2-) or [35S]taurine formed from labelled dietary cysteine.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Alkynes / pharmacology
  • Animals
  • Cystathionine beta-Synthase / metabolism
  • Cystathionine gamma-Lyase / metabolism
  • Cysteine / metabolism*
  • Glycine / analogs & derivatives
  • Glycine / pharmacology
  • Hydrogen Sulfide / metabolism
  • In Vitro Techniques
  • Kidney / drug effects
  • Kidney / enzymology*
  • Liver / drug effects
  • Liver / enzymology*
  • Male
  • Rats
  • Rats, Inbred Strains
  • Tissue Distribution
  • Transaminases / metabolism

Substances

  • Alkynes
  • propargylglycine
  • Transaminases
  • cysteine aminotransferase
  • Cystathionine beta-Synthase
  • Cystathionine gamma-Lyase
  • Cysteine
  • Glycine
  • Hydrogen Sulfide