title: [Effect of monovalent cations on the catalytic and spectral properties of tyrosine-phenol-lyase from Citrobacter intermedius].
abstract: The action of monovalent cations Li+, Na+, K+, Rb+, Cs+, NH4+ on catalytic and physico-chemical properties of bacterial tyrosine--phenol-lyase was investigated. It was shown that K+, Rb+, Cs+, NH4+ were the noncompetitive activators of the enzyme, Na+ was an inhibitor, Li+ did not influence the catalytic activity. The values of KA and Vmax were determined for the activators in the reaction of alpha, beta-elimination of L-tyrosine. Monovalent cations affect the absorption and CD spectra of the enzyme and its complex with the quasi-substrate--L-alanine. It was suggested that an activation of tyrosine phenollyase by monovalent cations was connected with the increase of the active protonated form of the holoenzyme (lambda max 420 mm) induced by the cations-activators.
mesh_terms: D002384:Catalysis; D002414:Cations, Monovalent / Q000494:pharmacology*; D055598:Chemical Phenomena; D002621:Chemistry; D002942:Circular Dichroism; D002954:Citrobacter / Q000187:drug effects / Q000201:enzymology*; D004789:Enzyme Activation / Q000187:drug effects; D007700:Kinetics; D008190:Lyases / Q000378:metabolism*; D013053:Spectrophotometry; D014447:Tyrosine Phenol-Lyase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D002414:Cations, Monovalent; D008190:Lyases; D014447:Tyrosine Phenol-Lyase
vernacular_title: Vliianie monovalentnykh kationov na kataliticheskie i spektral'nye svoĭstva tirozin-fenol-liazy iz Citrobacter intermedius.