Analysis of wheat mitochondrially encoded polypeptides by in organello labelling

The in organello labeling pattern in wheat (Triticum aestivum) mitochondria isolated from imbibed embryos were compared with those from the commonly u sed starting material, etiolated seedlings. Mitochondria from imbibed embry os proved to be metabolically more active than those from etiolated seedlin gs and produced a large number of strongly in organello-labeled polypeptide s. Immunoprecipitation of the labeled proteins enabled the identification o f mitochondrially encoded subunits of the respiratory chain complex I, some of which could not be detected by conventional Western blotting due to the ir high hydrophobicity. A method for mass isolation of wheat embryos is als o presented which allows easy preparation of large amounts of intact and hi ghly active mitochondria suitable for biochemical studies.