SDS-PAGE analysis of the endosperm and amyloplast
stromal fraction and immunoblot analysis of endosperm, amyloplast
stromal, and granule fractions. A, Samples (30 μg) of the endosperm
(En) and amyloplast stromal fraction (Am) were subjected to SDS-PAGE
followed by Coomassie Blue staining. The molecular mass standards from
top to bottom are myosin (200 kD), β-galactosidase (116.2 kD),
phosphorylase b (97.4 kD), bovine serum albumin (66.2 kD), ovalbumin
(45 kD), and carbonic anhydrase (31 kD). B, A sample (0.1 μg) of the
isolated 112-kD protein and samples (30 μg) of the endosperm,
amyloplast stromal, and granule fractions were subjected to immunoblot
analysis using anti-SP antibodies. C, Samples (30 μg) of the
endosperm, amyloplast stromal, and granule fractions were subjected to
immunoblot analysis using anti-starch synthase I antibodies. A portion
of the immunoblots is shown in B and C. The position of the 112-kD
protein is indicated in A and B, and the position of starch synthase I
(SSI) is indicated in C. The data shown in each A through C is
representative of two independent experiments.