These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.
Pubmed for Handhelds
PUBMED FOR HANDHELDS
Search MEDLINE/PubMed
Title: Kinetics and inhibition of recombinant human cystathionine gamma-lyase. Toward the rational control of transsulfuration. Author: Steegborn C, Clausen T, Sondermann P, Jacob U, Worbs M, Marinkovic S, Huber R, Wahl MC. Journal: J Biol Chem; 1999 Apr 30; 274(18):12675-84. PubMed ID: 10212249. Abstract: The gene encoding human cystathionine gamma-lyase was cloned from total cellular Hep G2 RNA. Fusion to a T7 promoter allowed expression in Escherichia coli, representing the first mammalian cystathionine gamma-lyase overproduced in a bacterial system. About 90% of the heterologous gene product was insoluble, and renaturation experiments from purified inclusion bodies met with limited success. About 5 mg/liter culture of human cystathionine gamma-lyase could also be extracted from the soluble lysis fraction, employing a three-step native procedure. While the enzyme showed high gamma-lyase activity toward L-cystathionine (Km = 0.5 mM, Vmax = 2.5 units/mg) with an optimum pH of 8.2, no residual cystathionine beta-lyase behavior and only marginal reactivity toward L-cystine and L-cysteine were detected. Inhibition studies were performed with the mechanism-based inactivators propargylglycine, trifluoroalanine, and aminoethoxyvinylglycine. Propargylglycine inactivated human cystathionine gamma-lyase much more strongly than trifluoroalanine, in agreement with the enzyme's preference for C-gamma-S bonds. Aminoethoxyvinylglycine showed slow and tight binding characteristics with a Ki of 10.5 microM, comparable with its effect on cystathionine beta-lyase. The results have important implications for the design of specific inhibitors for transsulfuration components.[Abstract] [Full Text] [Related] [New Search]