GC-MS analysis of monooxygenated diterpenes. Selective ion monitoring at m/z 288 detects monooxygenated taxanes, including chemically synthesized taxadiene 5α-ol (A) as well as those formed by recombinant bacteria expressing GGPPS, coTS79 and coCYP725A4/coTCPR fusion protein (B), recombinant bacteria expressing GGPPS, coTS79, coCYP725A4, and coTCPR (C), recombinant bacteria expressing GGPPS, coTS79, coCYP725A and hNPR (D), recombinant bacteria expressing GGPPS, coTS79, coTxCb5 and coCYP725A4/coTCPR fusion protein (E), and recombinant bacteria expressing GGPPS, coTS79, coCYP725A4 and coCYP725A4/coTCPR fusion protein (F). Peak 1 = T5α-ol; Peak 2 = OCT; Peak 3 = iso-OCT; and Peaks 4, 5 and 6 are presumed to be monooxygenated taxanes named TXO1, TXO2, and TXO3, respectively.