title: Kinetic Parameters and Cytotoxic Activity of Recombinant Methionine γ-Lyase from Clostridium tetani, Clostridium sporogenes, Porphyromonas gingivalis and Citrobacter freundii.
abstract: The steady-state kinetic parameters of pyridoxal 5'-phosphate-dependent recombinant methionine γ -lyase from three pathogenic bacteria, Clostridium tetani, Clostridium sporogenes, and Porphyromonas gingivalis, were determined in β- and γ-elimination reactions. The enzyme from C. sporogenes is characterized by the highest catalytic efficiency in the γ-elimination reaction of L-methionine. It was demonstrated that the enzyme from these three sources exists as a tetramer. The N-terminal poly-histidine fragment of three recombinant enzymes influences their catalytic activity and facilitates the aggregation of monomers to yield dimeric forms under denaturing conditions. The cytotoxicity of methionine γ-lyase from C. sporogenes and C. tetani in comparison with Citrobacter freundii was evaluated using K562, PC-3, LnCap, MCF7, SKOV-3, and L5178y tumor cell lines. K562 (IC50=0.4-1.3 U/ml), PC-3 (IC50=0.1-0.4 U/ml), and MCF7 (IC50=0.04-3.2 U/ml) turned out to be the most sensitive cell lines.
authors.affiliation: Engelhardt Institute of Molecular Biology, Russian Academy of Sciences, Vavilova Str., 32, Moscow, Russia, 119991.
authors.forename: E A
authors.initials: EA
authors.lastname: Morozova
authors.forename: V V
authors.initials: VV
authors.lastname: Kulikova
authors.forename: D V
authors.initials: DV
authors.lastname: Yashin
authors.forename: N V
authors.initials: NV
authors.lastname: Anufrieva
authors.forename: N Y
authors.initials: NY
authors.lastname: Anisimova
authors.forename: S V
authors.initials: SV
authors.lastname: Revtovich
authors.forename: M I
authors.initials: MI
authors.lastname: Kotlov
authors.forename: Y F
authors.initials: YF
authors.lastname: Belyi
authors.forename: V S
authors.initials: VS
authors.lastname: Pokrovsky
authors.forename: T V
authors.initials: TV
authors.lastname: Demidkina
keywords: cytotoxicity; kinetic parameters; methionine γ-lyase; oligomeric structure; pathogenic microorganisms