Rostrup M 2008 Amino Acids: Difference between revisions
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|title=Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger E, Haavik J (2008) Oxygen dependence of tyrosine hydroxylase. Amino Acids 34:455-64. | |title=Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger E, Haavik J (2008) Oxygen dependence of tyrosine hydroxylase. Amino Acids 34:455-64. | ||
|info=[http://www.ncbi.nlm.nih.gov/pubmed/17520326 PMID: 17520326] | |info=[http://www.ncbi.nlm.nih.gov/pubmed/17520326 PMID: 17520326] | ||
|authors=Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger | |authors=Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger Erich, Haavik J | ||
|year=2008 | |year=2008 | ||
|journal=Amino Acids | |journal=Amino Acids | ||
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|organism=Human | |organism=Human | ||
|preparations=Enzyme, Oxidase;biochemical oxidation | |preparations=Enzyme, Oxidase;biochemical oxidation | ||
|topics=Oxygen kinetics, Substrate | |||
|topics= | |pathways=ROX | ||
| | |||
|instruments=Oxygraph-2k | |instruments=Oxygraph-2k | ||
|discipline=Biomedicine | |discipline=Biomedicine | ||
}} | }} |
Latest revision as of 04:03, 23 November 2021
Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger E, Haavik J (2008) Oxygen dependence of tyrosine hydroxylase. Amino Acids 34:455-64. |
Rostrup M, Fossbakk A, Hauge A, Kleppe R, Gnaiger Erich, Haavik J (2008) Amino Acids
Abstract: The effects of dioxygen on tyrosine hydroxylase (TH) activity was studied, measuring the formation of DOPA from tyrosine, 3H2O from 3,5-3H-tyrosine, or by direct oxygraphic determination of oxygen consumption. A high enzyme activity was observed during the initial 1โ2 min of the reactions, followed by a decline in activity, possibly related to a turnover dependent substoichiometrical oxidation of enzyme bound Fe(II) to the inactive Fe(III) state. During the initial reaction phase, apparent Km-values of 29โ45 ยตM for dioxygen were determined for all human TH isoforms, i.e. 2โ40 times higher than previously reported for TH isolated from animal tissues. After 8 min incubation, the Km (O2)-values had declined to an average of 20 ยฑ 4 ยตM. Thus, TH activity may be severely limited by oxygen availability even atmoderate hypoxic conditions, and the enzyme is rapidly and turnover dependent inactivated at the experimental conditions commonly employed to measure in vitro activities. โข Keywords: Catecholamines, Human, Hypoxia, Oxygen, Tyrosine hydroxylase
โข O2k-Network Lab: AT Innsbruck Gnaiger E
Labels: MiParea: Instruments;methods
Organism: Human
Preparation: Enzyme, Oxidase;biochemical oxidation
Regulation: Oxygen kinetics, Substrate
Pathway: ROX HRR: Oxygraph-2k