title: The activity and reaction specificity of tyrosine phenol-lyase regulated by monovalent cations.
abstract: This work was aimed at studying the effect of monovalent inorganic cations (Li+, Na+, K+, Rb+, Cs+, NH+4) on the catalytic and spectral characteristics of tyrosine phenol-lyase from Citrobacter intermedius. These cations were shown to influence the proportion of the beta-elimination reaction rate to the rate of side transamination reaction. Most of the monovalent cations are non-competitive activators of the beta-elimination reaction; Li+ exerts no effect on the enzyme activity in this reaction; Na+ is an inhibitor of the beta-elimination reaction. The activation of tyrosine phenol-lyase by monovalent cations stems from the creation of an active holoenzyme form (lambda max 420 nm) due to conformational rearrangements of the protein molecule.
authors.affiliation: Engelhardt Institute of Molecular Biology, USSR Academy of Sciences, Moscow.
authors.forename: T V
authors.initials: TV
authors.lastname: Demidkina
authors.forename: I V
authors.initials: IV
authors.lastname: Myagkikh
mesh_terms: D002414:Cations, Monovalent / Q000494:pharmacology*; D002942:Circular Dichroism; D004789:Enzyme Activation; D007700:Kinetics; D008190:Lyases / Q000378:metabolism*; D015394:Molecular Structure; D013053:Spectrophotometry; D013379:Substrate Specificity; D014447:Tyrosine Phenol-Lyase / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D002414:Cations, Monovalent; D008190:Lyases; D014447:Tyrosine Phenol-Lyase