AMINO-ACID-ANALYSIS OF PROTEINS SEPARATED BY 2-DIMENSIONAL ELECTROPHORESIS IN MAIZE - ISOFORM DETECTION AND FUNCTION IDENTIFICATION

The possibility of using experimentally determined amino acid composit ion to assess relatedness between 75 proteins separated by two-dimensi onal electrophoresis (2-DE) and to identify them was tested on maize. Two independent parameters, the relative Euclidean distance and the co rrelation coefficient between the amino acid compositions, were evalua ted and used. Previous sequence information for 31 out of the 75 prote ins made it possible to evaluate the method for the detection of isofo rms and for identification. However, the extension of the interrogatio n beyond maize to all plant sequences raised the problem of false posi tives that could nevertheless be limited by replications and by using additional information. The efficiency of the method to assess related ness between proteins should make amino acid composition analysis a va luable tool in large protein characterization programs based on 2-DE, by facilitating the transfer of information from one well-documented o rgan/tissue or genotype to another.