Fig. 3

Plastid isolation and purity assessment. A Separation of plastids on a discontinuous sucrose gradient (0.75, 0.92, 1.20, 1.50 M) at three different coloring stages. B Light microscopy of purified chloroplasts from band 2 (I), plastid fractions were designated as bands 1, 2, 3, 4 from the top to the bottom of the sucrose gradient (II). C Assessment on the purity of isolated plastids using immunoblots. Purified plastids (band 2) were detected using antibodies for Tic110 (translocon at the inner envelope membrane of chloroplasts) and cytosolic UGPase. Each lane was loaded with 20 µg of total protein. The positions of the molecular markers are indicated on the left. Chlo, chloroplast; Chlo-Chro, intermediate plastids between chloroplasts and chromoplasts; Chro, chromoplast. D Coomassie blue protein profiles of purified plastids (band 2) from kumquat peel as compared with total kumquat peel proteins