A new activity of alkaline protease from Bacillus subtilis for Michael addition reactions of imidazole, 4-nitro-1H-imidazole and 2-methyl-4-nitro-1H-imidazole with acrylates and acrylic acid was investigated. The reactions were carried out in pyridine at 50 degreesC for 72 h. Five N-substituted imidazole derivatives were obtained using acrylate esters, but not acrylic acid, in yields from 62% to 76%.