Purification and characterization of cystathionine gamma-lyase from Lactobacillus fermentum DT41.
A homo-tetrameric ca. 140-kDa cystathionine gamma-lyase was purified to homogeneity from Lactobacillus fermentum DT41 by four chromatographic steps. This was the first enzyme responsible for amino acid catabolism purified from lactobacilli. The activity is pyridoxal-5'-phosphate dependent and the enzyme catalyzes the alpha,gamma-elimination reaction of L-cystathionine producing L-cysteine, ammonia and alpha-ketobutyrate. The cystathionine gamma-lyase produced a free thiol group, a keto acid component and ammonia from several amino acids, including L-cysteine and methionine, and amino acid derivatives. L-Cystine was the best substrate. The enzyme was stable in the conditions of cheese ripening and may contribute to the biosynthesis of sulfur-containing compounds.
Institute of Dairy Microbiology, Faculty of Agriculture, University of Perugia, Italy.
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Smacchi
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Gobbetti
D000596:Amino Acids / Q000032:analysis; D002611:Cheese / Q000382:microbiology; D003540:Cystathionine / Q000378:metabolism; D003542:Cystathionine gamma-Lyase / Q000037:antagonists & inhibitors / Q000302:isolation & purification* / Q000378:metabolism*; D003545:Cysteine / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005516:Food Microbiology; D006863:Hydrogen-Ion Concentration; D007778:Lactobacillus / Q000201:enzymology*; D013379:Substrate Specificity
D000596:Amino Acids; D004791:Enzyme Inhibitors; D003540:Cystathionine; D003542:Cystathionine gamma-Lyase; D003545:Cysteine