Abstract
Plastids possess a remarkable capacity to differentiate, dedifferentiate or redifferentiate to chloroplast, ethioplast or chromoplast. Each plastid plays indispensable roles not only in photosynthesis but also in the production of fatty acids, amino acids, carotenoids and terpenoids. To understand the basic mechanism of plastid differentiation, we prepared and analyzed proteins from various types of plastid using proteomic approaches. We succeeded in isolating intact chloroplasts, and etioplasts from Arabidopsis and chromoplasts from tomatoes (Micro-Tom) by Nycodenz gradient centrifugation, which enables us to prepare the continuous density gradient easily and separate highly pure mutant's plastids from other cell organelles. We also succeeded in isolation plastids from the mutants, apg3 and apg2, which has abnormal thylakoids . After a serial extraction of proteins from the isolated plastids based on solubility, we applied the protein samples to two-dimensional gel electrophoresis. Protein spots were isolated and identified by MALDI/TOFMS and MASCOT Software.
