Enzymatic release of amino acids from different humic substances

Jahnel, Jutta; Frimmel, Fritz H.

doi:10.1002/aheh.19950230107

Cited by 16 publications

(7 citation statements)

References 12 publications

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“…The nature of these materials is undergoing a major redefinition from a complex poly-condensed macromolecular structure (Schulten and Schnitzer 1993) to a less strongly bonded dynamic complex of smaller distinct molecules that include mainly plant and microbial constituents and their partial decomposition products held together by H-bonding, hydrophobic interactions and covalent bonds (Burdon 2001;Piccolo 2001;Sutton and Sposito 2005;Kleber et al 2006, this volume;). The presence of protein in humic extracts has been implied by release of amino acids by acid hydrolysis (Bremner 1965) and proteolytic enzymes (Ladd and Brisbane 1967;Jahnel and Frimmel 1995). Knicker and Hatcher (1997) and Zang et al (2000) have suggested that proteins might be provided long-term protection by their incorporation into hydrophobic domains of soil organic matter.…”

Section: Carbohydratesmentioning

confidence: 98%

Role of proteins in soil carbon and nitrogen storage: controls on persistence

et al. 2007

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Mechanisms of soil organic carbon (C) and nitrogen (N) stabilization are of great interest, due to the potential for increased CO 2 release from soil organic matter (SOM) to the atmosphere as a result of global warming, and because of the critical role of soil organic N in controlling plant productivity. Soil proteins are recognized increasingly as playing major roles in stabilization and destabilization of soil organic C and N. Two categories of proteins are proposed: detrital proteins that are released upon cell death and functional proteins that are actively released into the soil to fulfill specific functions. The latter include microbial surface-active proteins (e.g., hydrophobins, chaplins, SC15, glomalin), many of which have structures that promote their persistence in the soil, and extracellular enzymes, responsible for many decomposition and nutrient cycling transformations. Here we review information on the nature of soil proteins, particularly those of microbial origin, and on the factors that control protein persistence and turnover in the soil. We discuss first the intrinsic properties of the protein molecule that affect its stability, next possible extrinsic stabilizing influences that arise as the proteins interact with other soil constituents, and lastly controls on accessibility of proteins at coarser spatial scales involving microbial cells, clay particles, and soil aggregates. We conclude that research at the interface between soil science and microbial physiology will yield rapid advances in our understanding of soil proteins. We suggest as research priorities determining the relative abundance and turnover time (age) of microbial versus plant proteins and of functional microbial proteins, including surfaceactive compounds.

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Section: Carbohydratesmentioning

confidence: 98%

Role of proteins in soil carbon and nitrogen storage: controls on persistence

et al. 2007

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“…ER1 FA and ER3-NaOH HA were extracted from soil with sodium hydroxide (c (eq)"0.1 mol/L), ER2-2 HA was extracted with sodium pyrophosphate (c(eq)"0.1 mol/L). The samples from surface water HEN1 and HEN2 were preparated without separating a FA and HA fraction [6].…”

Section: Methodsmentioning

confidence: 99%

“…In J.B. Jahnel ( ) · F.H. Frimmel Engler-Bunte-Institut der Universita¨t Karlsruhe, Bereich Wasserchemie, D-76128 Karlsruhe, Germany aquatic HS up to 2% nitrogen have been determined usually [6]. The common method for nitrogen characterization studies is the classical acid hydrolysis.…”

Section: Introductionmentioning

confidence: 99%

“…They are polyfunctional refractory substances, which are fairly resistant to biological decomposition [1,2]. Because HS contribute significantly to the biogeochemically important bound nitrogen in the biosphere, there is a great interest to characterize the bound nitrogen forms of these compounds [3][4][5][6][7]. The nitrogen content of soil humic acids (HA) amounts to 6%, while soil fulvic acids (FA) only contain 3% at most [4].…”

Section: Introductionmentioning

confidence: 99%

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Detection of glucosamine in the acid hydrolysis solution of humic substances

Jahnel

Frimmel

1996

Analytical and Bioanalytical Chemistry

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Several humic substances isolated from water and soil have been characterized applying acid hydrolysis to release defined components bound in these high molecular organic compounds. The hydrolysis solution have been analyzed by HPLC after precolumn derivatization with o-phthalaldehyde and 9-fluorenylmethylchloroformate. Under these conditions the nitrogen containing carbohydrate glucosamine could be detected and separated besides seventeen amino acids. The results show that 8.0 to 40.1% of the total nitrogen content of the investigated samples contributes to amino acids and up to 7.9% to the carbohydrate glucosamine. It could be deduced that defined amino acid carbohydrate building blocks were bound in humic substances, because the glucosamine nitrogen content correlates with the calculated amino acid nitrogen. Furthermore the total amino acid nitrogen amount of natural organic matter can be estimated from the results of the determination of glucosamine.

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“…40,41 Furthermore other organic molecules like amino acids, sugars and peptides can be incorporated leading to a broad range of different structural features. 42,43 Unfortunately, the very low concentration of those natural iron chelators in seawater makes the detection and characterization of them challenging. 44 Being aware of the importance of those natural macromolecules for marine microorganisms it is of large interest to nd synthetic compounds that are comparable to AHS, regarding their iron binding and transport properties in sea water, as well as their capability of providing bioavailable iron to algae.…”

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confidence: 99%

Benzoic hydroxamate-based iron complexes as model compounds for humic substances: synthesis, characterization and algal growth experiments

et al. 2016

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A series of monomeric and dimeric Fe III complexes bearing benzoic hydroxamates as O,O-chelates has been prepared and characterized by elemental analysis, IR spectroscopy, UV-Vis spectroscopy, electrospray ionization mass spectrometry (ESI-MS), cyclic voltammetry, EPR spectroscopy and for some examples by X-ray diffraction analysis. The stability of the synthesized complexes in pure water and seawater was monitored over 24 h by means of UV-Vis spectrometry. The ability to release iron from the synthesized model complexes has been investigated with algae growth experiments.

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Enzymatic release of amino acids from different humic substances

Cited by 16 publications

References 12 publications

Role of proteins in soil carbon and nitrogen storage: controls on persistence

Role of proteins in soil carbon and nitrogen storage: controls on persistence

Detection of glucosamine in the acid hydrolysis solution of humic substances

Benzoic hydroxamate-based iron complexes as model compounds for humic substances: synthesis, characterization and algal growth experiments

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