The degradation of exogenous LHCII as affected by
the concentration of thylakoid membrane protein in assay mixtures (A)
or the concentration of exogenous LHCII added (B). A, Exogenous
LHCII apoprotein (5 μg) was added to increasing amounts of
TX-100-solubilized PLB protein obtained from 8-d-old etiolated plants
in assay mixtures of 35 μL (0.5% TX-100, 40 mm Tris HCl,
pH 8.6). B, To nonsolubilized primary thylakoid protein (40 μg)
obtained from 6-d-old etiolated plants kept in the dark for 48 h
after a 2-min light pulse, increasing amounts of exogenous LHCII
apoprotein were added in assay mixtures of 48 μL (0.25% TX-100, 40
mm Tris-HCl, pH 8.6). Proteolytic activity is based on the
amount of exogenous LHCII apoprotein remaining after 45 min (A) or 15
min (B) of incubation at 37°C as monitored by immunodetection on
western blots.