title: Complete proteomic-based enzyme reaction and inhibition kinetics reveal how monolignol biosynthetic enzyme families affect metabolic flux and lignin in Populus trichocarpa.
abstract: We established a predictive kinetic metabolic-flux model for the 21 enzymes and 24 metabolites of the monolignol biosynthetic pathway using Populus trichocarpa secondary differentiating xylem. To establish this model, a comprehensive study was performed to obtain the reaction and inhibition kinetic parameters of all 21 enzymes based on functional recombinant proteins. A total of 104 Michaelis-Menten kinetic parameters and 85 inhibition kinetic parameters were derived from these enzymes. Through mass spectrometry, we obtained the absolute quantities of all 21 pathway enzymes in the secondary differentiating xylem. This extensive experimental data set, generated from a single tissue specialized in wood formation, was used to construct the predictive kinetic metabolic-flux model to provide a comprehensive mathematical description of the monolignol biosynthetic pathway. The model was validated using experimental data from transgenic P. trichocarpa plants. The model predicts how pathway enzymes affect lignin content and composition, explains a long-standing paradox regarding the regulation of monolignol subunit ratios in lignin, and reveals novel mechanisms involved in the regulation of lignin biosynthesis. This model provides an explanation of the effects of genetic and transgenic perturbations of the monolignol biosynthetic pathway in flowering plants.
authors.affiliation: State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
authors.forename: Jack P
authors.initials: JP
authors.lastname: Wang
authors.forename: Punith P
authors.initials: PP
authors.lastname: Naik
authors.forename: Hsi-Chuan
authors.initials: HC
authors.lastname: Chen
authors.forename: Rui
authors.initials: R
authors.lastname: Shi
authors.forename: Chien-Yuan
authors.initials: CY
authors.lastname: Lin
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.forename: Christopher M
authors.initials: CM
authors.lastname: Shuford
authors.forename: Quanzi
authors.initials: Q
authors.lastname: Li
authors.forename: Ying-Hsuan
authors.initials: YH
authors.lastname: Sun
authors.forename: Sermsawat
authors.initials: S
authors.lastname: Tunlaya-Anukit
authors.forename: Cranos M
authors.initials: CM
authors.lastname: Williams
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
authors.forename: Joel J
authors.initials: JJ
authors.lastname: Ducoste
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Sederoff
authors.forename: Vincent L
authors.initials: VL
authors.lastname: Chiang
mesh_terms: D007700:Kinetics; D008031:Lignin / Q000378:metabolism*; D013058:Mass Spectrometry; D010940:Plant Proteins / Q000378:metabolism*; D020641:Polymorphism, Single Nucleotide; D032107:Populus / Q000378:metabolism*; D020543:Proteome
chemical_list: D010940:Plant Proteins; D020543:Proteome; D008031:Lignin