AbstractReversible polymerisation and A + B ⇌ C type reactions among proteins during zone electrophoresis may give rise to tailing, extra bands and mobility changes. One or more of these signs are likely to appear with the milder type of interaction, i.e. equilibrium constant in the range 102–108, whether the time to equilibrium is measured in hours or less. Two‐dimensional electrophoresis is more useful for diagnosing interactions. No definite evidence has been obtained for protein‐protein interactions among the slow‐moving gliadins of Bison and Cappelle varieties and the total number of bands probably represents the minimum number of molecular species present.The electrophoretic pattern of a given variety does not appear to alter qualitatively when the year or place of growth is changed. It is estimated that a wheat protein concentration needs to be above ∼0·1 mg/ml to be observable on a starch gel.