Associations between lipoxygenases (Lox) and 14-3-3 proteins were demonstrated by two different methods, First, immunoprecipitation experiments, using isoenzyme-specific monoclonal Lox antibodies, showed that 14-3-3 proteins coprecipitate with 13-Lox, but not with the 9-Lox from barley. Second, interactions between 13-Lox and 14-3-3 were established by surface plasmon resonance studies, showing that 13-Lox binds with 14-3-3 proteins in a concentration-dependent manner. The interactions between 14-3-3 proteins and 13-Lox may reveal their role during plant development, (C) 2000 Federation of European Biochemical Societies.