We describe cloning and characterization of three rice (Oryza sativa) NADPH-cytochrome P450 reductases (OsCPRs; E.C.22.214.171.124) that are potential donors to plant P450s, including tryptamine 5-hydroxylase (T5H) in serotonin synthesis and cinnamate 4-hydroxylase (C4H) in phenylpropanoid synthesis. All three OsCPR transcripts are induced to varying degrees by stresses. Co-expression of full-length OsCPR1, OsCPR2 and OsCPR3 with either T5H or C4H in E. coli indicated that the OsCPR2/T5H and OsCPR2/C4H constructs displayed the highest T5H and C4H catalytic activities. The N-terminal residues of OsCPR2 were required for peak electron transfer activity to P450 even though deletion mutants with short N-terminal deletions were capable of reducing cytochrome c.
- 4-Coumaric acid
- Cinnamate 4-hydroxylase
- E. coli expression
- NADPH-dependent cytochrome P450 reductases
- Oryza sativa; serotonin synthesis
- Tryptamine 5-hydroxylase
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