Immunolocalization of phenylalanine ammonia-lyase and cinnamate-4-hydroxylase in differentiating xylem of poplar.
Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) and cinnamate-4-hydroxylase (C4H; EC 1.14.13.11) are pivotal enzymes involved in lignification. We synthesized peptides as the epitopes according to the amino acid sequences of these enzymes, coupled them with hemocyanin, and injected them into mice. The antiserums against peptides of PAL and C4H specifically detected PAL and C4H in the crude enzymes extracted from differentiating xylem of poplar, respectively. PAL and C4H were localized in differentiating xylem of poplar. PAL labeling was mainly localized in the cytosol, and somewhat localized on the rough-endoplasmic reticulum (r-ER) and the Golgi apparatus. In contrast, C4H was mainly observed on r-ER and the Golgi apparatus. These findings suggest that conversion of phenylalanine to cinnamic acid occurs in the cytosol and the following reaction occurs near the membrane of r-ER and the Golgi apparatus. The possibility of coordinated localization of PAL and C4H is discussed.
Sato
Takahiko
T
Laboratory of Tree Cell Biology, Graduate School of Agriculture, Kyoto University, Sakyo, Kyoto 606-8502, Japan.
Takabe
Keiji
K
Fujita
Minoru
M
D003577:Cytochrome P-450 Enzyme System / Q000032:analysis*; D007118:Immunoassay; D006899:Mixed Function Oxygenases / Q000032:analysis*; D010650:Phenylalanine Ammonia-Lyase / Q000032:analysis*; D018514:Plant Structures / Q000737:chemistry*; D032107:Populus / Q000737:chemistry*; D050564:Trans-Cinnamate 4-Monooxygenase
D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D050564:Trans-Cinnamate 4-Monooxygenase; D010650:Phenylalanine Ammonia-Lyase