4.2.1.19 D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate = 3-(imidazol-4-yl)-2-oxopropyl phosphate + H2O energy of activation 14700 cal/mol 5535 4.2.1.19 D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate = 3-(imidazol-4-yl)-2-oxopropyl phosphate + H2O energy of activation 15900 cal/mol 5534 4.2.1.19 D-erythro-1-(imidazol-4-yl)glycerol 3-phosphate = 3-(imidazol-4-yl)-2-oxopropyl phosphate + H2O highly stereospecific, inversion of configuration at C3 5544