Bacterial cytochromes P‐450

Summary The cytochromes P‐450 (P‐450s) constitute an extremely large family ('superfamily') of haemoproteins that catalyse the oxidation of a wide range of physiological and non‐physiological compounds. A remarkable feature of the P‐450s is the manipulation of the same basic structure and chemistry to achieve an enormous range of functions in organisms as diverse as bacteria and man. Indeed, the P‐450s have been described as ‘the most versatile biological catalyst known’. Much research is focussed on mammalian P‐450s, with their roles in such processes as steroid transformations and the metabolism of carcinogens and other xenobiotics. However, our knowledge of the structure and function of the P‐450s has been advanced by analysis of a limited number of its bacterial members, primarily P‐450cam from Pseudomonas putida. Four P‐450 structures have been solved to date, all of which are from bacterial sources. The aim of this review is to assess current knowledge of the many bacterial P‐450s, with emphasis on their diverse biological roles and on the advances in our knowledge of this extremely important enzyme class, which have been made feasible through their study.