Figure 6.
UreG-dependent in vitro activation of urease. A, nickel-fertilized and non-fertilized N. benthamiana plants (⊕ or ⊝) were used to transiently express Arabidopsis UreG or to co-express urease together with UreD and UreF (UreG and UreD were Strep-tagged). Clarified and desalted extracts of these plants (G and UDF) were mixed with each other or with the extract of a control plant (C) not expressing any proteins and incubated for the indicated times. After incubation urea was added, and the urease activity was determined. B, the experiment was in part repeated and expanded mixing clarified and desalted extracts (index: x) and purified proteins (index: p). For purification, N-terminally Strep-tagged UreG (for Gp) and UreD (for UDFp) were employed. Activation assays were carried out in triplicate (individual data points shown as open circles) in both experiments (error bars = S.D.).