DOI: 10.1007/s10533-014-0030-y
Scopus记录号: 2-s2.0-84918514518
论文题名: Extracellular enzyme kinetics scale with resource availability
作者: Sinsabaugh R.L. ; Belnap J. ; Findlay S.G. ; Shah J.J.F. ; Hill B.H. ; Kuehn K.A. ; Kuske C.R. ; Litvak M.E. ; Martinez N.G. ; Moorhead D.L. ; Warnock D.D.
刊名: Biogeochemistry
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2014
卷: 121, 期: 2 起始页码: 287
结束页码: 304
语种: 英语
英文关键词: Ecological stoichiometry
; Enzyme kinetics
; Extracellular enzymes
; Microbial community
; Microbial metabolism
Scopus关键词: biogeochemistry
; enzyme activity
; homeostasis
; microbial community
; organic carbon
; reaction kinetics
; resource availability
; stoichiometry
英文摘要: Microbial community metabolism relies on external digestion, mediated by extracellular enzymes that break down complex organic matter into molecules small enough for cells to assimilate. We analyzed the kinetics of 40 extracellular enzymes that mediate the degradation and assimilation of carbon, nitrogen and phosphorus by diverse aquatic and terrestrial microbial communities (1160 cases). Regression analyses were conducted by habitat (aquatic and terrestrial), enzyme class (hydrolases and oxidoreductases) and assay methodology (low affinity and high affinity substrates) to relate potential reaction rates to substrate availability. Across enzyme classes and habitats, the scaling relationships between apparent Vmax and apparent Km followed similar power laws with exponents of 0.44 to 0.67. These exponents, called elasticities, were not statistically distinct from a central value of 0.50, which occurs when the Km of an enzyme equals substrate concentration, a condition optimal for maintenance of steady state. We also conducted an ecosystem scale analysis of ten extracellular hydrolase activities in relation to soil and sediment organic carbon (2,000–5,000 cases/enzyme) that yielded elasticities near 1.0 (0.9 ± 0.2, n = 36). At the metabolomic scale, the elasticity of extracellular enzymatic reactions is the proportionality constant that connects the C:N:P stoichiometries of organic matter and ecoenzymatic activities. At the ecosystem scale, the elasticity of extracellular enzymatic reactions shows that organic matter ultimately limits effective enzyme binding sites. Our findings suggest that one mechanism by which microbial communities maintain homeostasis is regulating extracellular enzyme expression to optimize the short-term responsiveness of substrate acquisition. The analyses also show that, like elemental stoichiometry, the fundamental attributes of enzymatic reactions can be extrapolated from biochemical to community and ecosystem scales. © 2014, Springer International Publishing Switzerland. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/83609
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: Biology Department, University of New Mexico, Albuquerque, NM, United States; Southwest Biological Science Center, U.S. Geological Survey, Moab, UT, United States; Cary Institute of Ecosystem Studies, Millbrook, NY, United States; Watershed Sciences Department, Utah State University, Logan, UT, United States; National Health and Environmental Effects Laboratory, Mid-Continent Ecology Division, Office of Research and Development, U.S. Environmental Protection Agency, Duluth, MN, United States; Department of Biological Sciences, University of Southern Mississippi, Hattiesburg, MS, United States; Bioscience Division, Los Alamos National Laboratory, Los Alamos, NM, United States; Department of Environmental Science, University of Toledo, Toledo, OH, United States
Recommended Citation:
Sinsabaugh R.L.,Belnap J.,Findlay S.G.,et al. Extracellular enzyme kinetics scale with resource availability[J]. Biogeochemistry,2014-01-01,121(2)