Abstract
Protein complexes of photosynthetic and respiratory electron transport chains are composed of hydrophobic membrane proteins. The recent development of the proteomics and the genome information facilitates the identification of hydrophilic proteins of organisms whose genomes have been resolved. However, it is still difficult to identify membrane proteins.
To challenge this difficulty, we tried to develop a method to determine internal amino acid sequences of D1 protein of photosystem II whose N-termimus is blocked. D1 was separated by denaturing electrophoresis and extracted from the gel in a solution containing SDS after staining by Coomassie Blue. SDS in the elution medium which was necessary to keep extracted D1 solubilized prohibited the attack of trypsin. We found that Coomassie Blue can effectively complement the role of SDS assisting the digestion of D1 by trypsin. This method will be a help for the proteomic analysis of membrane proteins in organisms whose genomes are not resolved.
