Fig. 1.

Microsomal membranes from the moss Funaria hygrometrica were incubated on ice with 83 nM ³H IAA for 30 min in dark followed by the addition of increasing concentrations of non-radioactive IAA (0, 6.25, 12.5, 25, 50 and 100 μM) in six different reaction tubes. The reaction mixture was filtered through cellulose acetate filters, washed with binding buffer and the radioactivity is determined. The standard deviation of triplicate filters was plotted as a function of concentration of IAA. The concentration corresponding to ~K _m is shown by an arrow. The variation between samples by the filter assay was observed to be <5%