Transition vesicle-enriched fractions isolated from rat liver exhibit a unique peptide pattern

Summary Isolated fractions enriched in transition vesicles isolated by preparative free-flow electrophoresis from transition elements of endoplasmic reticulum incubated with ATP and a cytosol fraction in a cell free system, exhibited a polypeptide composition distinct from that of the original transitional endoplasmic reticulum fractions. The transition vesicles were deficient in peptides of apparent molecular mass between 200 and 270 kD, in the vicinity of 65 kD and less than 40 kD. Immunoblot analysis suggested a 140 kD protein to be concentrated in transition vesicles and low or absent from the endoplasmic reticulum fractions from which the transition vesicles were derived.