Cytochromes P-450 catalyze the formation of marchantins A and C in Marchantia polymorpha
作者:Susanne Friederich、Martina Rueffer、Yoshinori Asakawa、Meinhart H. Zenk
DOI:10.1016/s0031-9422(99)00340-4
日期:1999.12
Two specific cytochrome P-450 enzymes were detected in cell suspension cultures of Marchantla polymorpha; the first catalyzes the coupling of two molecules of lunularic acid to form marchantin C and CO2 and the second hydroxylates marchantin C to marchantin A. Cell free experiments using H-3/C-14 doubly-labeled substrates demonstrated that lunularic acid: and neither lunularine nor prelunularic acid, is the sole substrate for the coupling reaction. Both enzymes are dependent on the: presence of oxygen and NADPH. Both reactions were inhibited in the presence of CO in the dark; this inhibition was partially reversed by white light. In addition, both reactions were inhibited by typical inhibitors of cytochrome P-450 enzymes such as cytochrome c and ancymidol. (C) 1999 Elsevier Science Ltd. All rights reserved.
Synthesis of tritium labeled isotopomers ofL-tyrosine
The synthesis of four selectively labeled isotopomers of L-tyrosine, (L-Tyr), using chemical and enzymatic methods is reported. Four tritium labeled isotopomers of L-phenylalanine (L-Phe) – [2-3H]-, [2′,6′-3H2]-, [3R-3H]- and [3S-3H]- have been synthesized using a combination of chemical and enzymatic methods. The labeled isotopomers of L-Phe have been converted into [2 -3H]-, [2′,6′-3H2]-, [3R-3H]-