摘要：

47 Introduction 48 As part of carbon recycling in nature, microbial metabolism of camphor, a bicyclic 49 terpenoid naturally produced in leaves and wood of the camphor laurel (Cinnamomum 50 camphora) and available as (+) and (̛) isomeric forms, was studied by Gunsalus as early as 51 1959 using a sewage sludge-derived pseudomonad (strain P or C1B), now known as 52 Pseudomonas putida ATCC 17453 (=NCIMB 10007) (10). After several elegant studies, 53 including the identification of a large transmissible CAM plasmid controlling camphor 54 metabolism in P. putida (49), cleavage of the bicyclic ring of camphor was found to 55 involve the participation of three unrelated monooxygenases, one dehydrogenase and one 56 CoA ester synthetase (13-15, 44, 58) (Fig. 1). The FAD- and NADPH-dependent 2-oxo- 57 ǻ3-4,5,5-trimethylcyclopentenylacetyl-CoA 1,2-monooxygenase (OTEMO), sometimes 58 referred to as MO2 (25, 63), was one of the first identified members of the type 1 ring- 59 expanding BVMOs (EC 1.14.13.xx), the prototype and most studied being the 60 cyclohexanone monooxygenase (CHMO) of Acinetobacter sp. NCIMB 9871 (55, 61, 63). 61 Type 1 BVMOs are thus far more frequently found among microorganisms than those of 62 type 2 which require FMN as prosthetic group and NADH as cofactor (34, 63). 63 BVMOs carry out highly regio- and enantioselective nucleophilic and electrophilic 64 oxygenation of a variety of ketonic substrates. BVMOs are also known to catalyze 65 epoxidations and S- and N-heteroatom oxidations (for recent reviews: 4, 18, 29, 33, 34). 66 The BVMO-catalyzed reaction is recognized by pharmaceutical manufacturers as one of 67 the green chemistry priority research areas in order to reduce use of chlorinated solvents 68 or strong oxidants (16, 56). The generally accepted mechanism of BVMO based on 69 various kinetic studies indicates that NADPH binds first in the active site and is the last to 70 leave at the end of the catalytic cycle (50, 53, 57). Non-covalently bound FAD is reduced

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