Characterization of 2-D proteome maps based on the nearest neighborhoods of spots

A novel approach to the construction of invariants for characterization of 2-D maps, such as 2-D proteome maps, 2-D NMR spectral maps, etc., is put forward. The approach is based on consideration of the neighborhood of points (spots) of the map and it is sufficiently flexible to allow one to vary not only the number of nearest neighbor spots used in characterization of a map but also the density of information on the relative distance of the selected map points. The method is illustrated with a Coomassie brilliant blue stained 2-D gel electrophoresis pattern of the Fisher F344 rat liver proteome.