Microbial ACC deaminase catalyses the conversion of 1-aminocyclopropan
e-1-carboxylate (ACC), the precursor to the phytohormone ethylene, to
ammonia and alpha-ketobutyrate. We screened microorganisms for ACC deg
rading ability and cloned and sequenced the ACC deaminase genes from t
wo Pseudomonas strains which displayed high enzyme activity. One of th
e genes was homologous with two previously sequenced ACC deaminase gen
es, but the other was different.