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B6db references: 10194060

type Journal Article
authors Chu, L.; Ebersole, J. L.; Kurzban, G. P.; Holt, S. C.
title Cystalysin, a 46-kDa L-cysteine desulfhydrase from Treponema denticola: biochemical and biophysical characterization
journal Clin Infect Dis
sel selected
ui 10194060
year (1999)
volume 28
number 3
pages 442-50
keywords Cystathionine gamma-Lyase/genetics/*isolation & purification/*metabolism
abstract A 46-kDa hemolytic protein referred to as cystalysin, from Treponema denticola ATCC 35404, was characterized and overexpressed in Escherichia coli LC-67. Cystalysin lysed erythrocytes, hemoxidized hemoglobin to sulfhemoglobin and methemoglobin, and removed the sulfhydryl and amino group from selected S-containing compounds (e.g., cysteine) producing H2S, NH3, and pyruvate. With L-cysteine as substrate, cystalysin obeys Michaelis-Menten kinetics. Cystathionine and s-aminoethyl-L-cysteine were also substrates. Several of the small alpha amino acids were found to be competitive inhibitors of cystalysin. The enzymatic activity was increased by beta- mercaptoethanol and was not inhibited by the proteinase inhibitor TLCK (N alpha-p-tosyl-L-lysine chloromethyl ketone), pronase, or proteinase K, suggesting the functional site was physically protected or located in a small fragment of the polypeptide. We hypothesize that cystalysin is a pyridoxal-5-phosphate-containing enzyme with the activity of an alphaC-N and betaC-S lyase (cystathionase). Since high amounts of H2S have been reported in deep periodontal pockets, this metabolic enzyme from T. denticola may also function in vivo as an important virulence molecule.
last changed 2017/09/08 10:12

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