|
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 |
Activity |
4.4.1.28 |
Family |
4.4.1.28.a |
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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