DOI: 10.1007/s10533-015-0086-3
Scopus记录号: 2-s2.0-84928938258
论文题名: Catalytic kinetics and activation energy of soil peroxidases across ecosystems of differing lignin chemistries
作者: Triebwasser-Freese D.J. ; Tharayil N. ; Preston C.M. ; Gerard P.G.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2015
卷: 124, 期: 2018-01-03 起始页码: 113
结束页码: 129
语种: 英语
英文关键词: Activation energy
; Km
; Lignin
; Michaelis–Menten
; Oxidoreductase
; Peroxidase
; Soil enzyme
; Vmax
Scopus关键词: activation energy
; agricultural ecosystem
; catalysis
; coniferous forest
; deciduous forest
; enzyme
; kinetics
; lignin
; residence time
; soil ecosystem
英文摘要: Factors regulating the persistence of lignin in terrestrial ecosystems are highly debated, and recently lignin has been proposed to have a low residence time in soils. The catalytic efficiency and activation energy of the oxidoreductase enzymes regulate the residence time of lignin in soils. We characterized the spatial and seasonal changes in the apparent Michaelis–Menten kinetics and activation energy of soil peroxidases in three ecosystems of differing litter chemistries- pine forest, deciduous forest, and agricultural ecosystem. Peroxidases rarely follow true Michaelis–Menten kinetics, hence we measured the apparent Km (AppKm ) and apparent Vmax (AppVmax ) of soil peroxidases under potentially H2 O2 non-limiting conditions using 3,3′,5,5′-tetramethylbenzidine as the reducing substrate. The AppVmax and AppKm measured in this study, when used independently, exhibited only a weak relationship with total quantity and composition of lignins. Hence, we adopted the ratio of these two parameters (AppVmax /AppKm ) to define the apparent catalytic efficiency (AppCE) of peroxidases. Across the three ecosystems and seasons, the AppCE of peroxidase was ecosystem specific, and exhibited a strong correlation with the monolignol composition of the resident plant species. The AppCE of peroxidase was higher in agricultural soils that had lower lignin content. Pine soils with a higher relative proportion of vanillyl units that contribute to more recalcitrant inter-unit linkages in lignins exhibited the highest AppVmax and AppKm , resulting in the lowest AppCE. This decoupling of AppCE of peroxidases from chemistry of the native lignin observed in our assay-system could indicate a relatively longer persistence of lignin in ecosystems receiving recalcitrant litter inputs. Even though the apparent activation energy (AppEa) of peroxidases varied by depth and seasons across ecosystems, the AppEa did not relate to the chemistry or quantity of lignins, probably due to the substrate-saturated assay conditions. Our study captures the apparent kinetics of peroxidases in soils, which was ecosystem specific, and in part regulated by the composition of monolignols, thus providing a preliminary linkage between lignin chemistry and enzyme properties in natural systems. © 2015, Springer International Publishing Switzerland. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83501
Appears in Collections: 气候减缓与适应 气候变化事实与影响
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作者单位: School of Agriculture, Forestry and Environmental Sciences, Clemson University, Clemson, SC, United States; Natural Resources Canada, Pacific Forestry Centre, Victoria, BC, Canada; Mathematical Sciences, Clemson University, Clemson, SC, United States
Recommended Citation:
Triebwasser-Freese D.J.,Tharayil N.,Preston C.M.,et al. Catalytic kinetics and activation energy of soil peroxidases across ecosystems of differing lignin chemistries[J]. Biogeochemistry,2015-01-01,124(2018-01-03)