[Isolation, purification and some properties of tyrosine-phenol-lyase from Citrobacter freundii cells]

A new procedure for isolation of tyrosine-phenol-lyase from the cells of C. freundii strain 62 allowing to obtain a highly purified enzyme with a high yield at a reduced time expenditure has been developed. The procedure described differs from the well-known method for isolation of the enzyme from the cells of Escherichia intermedia and Erwinia herbicola. Some properties of the enzyme from C. freundii 62, e.g. stability, dependence of the enzyme activity on some mono- and bivalent cations and pH- and temperature dependences of the enzyme have been studied. It was shown that the enzyme is activated by NH4+, K+, Na+ and is inhibited by Ca2+, Cu2+ and Mg2+. The enzyme loses up to 50% of its activity upon storage in glycerol with 2-mercaptoethanol during 1,5 months at -18 degrees.