Difference between revisions of "Phosphorylation pathway"
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The '''phosphorylation system''' is the functional unit utilizing the protonmotive force to phosphorylate ADP (D) to ATP (T), and may be defined more specifically as the DT-phosphorylation system or '''DT-system'''. The DT-system consists of [[adenylate nucleotide translocase]], [[phosphate carrier]], and [[ATP synthase]]. Mitochondrial [[adenylate kinase]], mt-[[creatine kinase]] and mt-[[hexokinase]] constitute extended components of the DT-phosphorylation system, controlling local AMP and ADP concentrations and forming [[metabolic channel]]s. Since substrate-level phosphorylation is involved in the TCA-cycle, the mtDT system includes succinyl-CoA synthase (GDP to GTP or ADP to ATP). | The '''phosphorylation system''' is the functional unit utilizing the protonmotive force to phosphorylate ADP (D) to ATP (T), and may be defined more specifically as the DT-phosphorylation system or '''DT-system'''. The DT-system consists of [[adenylate nucleotide translocase]], [[phosphate carrier]], and [[ATP synthase]]. Mitochondrial [[adenylate kinase]], mt-[[creatine kinase]] and mt-[[hexokinase]] constitute extended components of the DT-phosphorylation system, controlling local AMP and ADP concentrations and forming [[metabolic channel]]s. Since substrate-level phosphorylation is involved in the TCA-cycle, the mtDT system includes succinyl-CoA synthase (GDP to GTP or ADP to ATP). | ||
|info=[[Gnaiger 2009 Int J Biochem Cell Biol]] | |info=[[Gnaiger 2009 Int J Biochem Cell Biol]] | ||
}} | }} | ||
{{MitoPedia concepts | {{MitoPedia concepts | ||
|mitopedia concept=MiP concept, SUIT concept | |mitopedia concept=MiP concept, SUIT concept | ||
}} | }} | ||
{{MitoPedia topics | {{MitoPedia topics | ||
|mitopedia topic=Enzyme | |mitopedia topic=Enzyme | ||
}} | }} | ||
Communicated by [[Gnaiger E]] 2010-08-15, edited 2016-08-26. | |||
== OXPHOS and substrate level phosphorylation == | == OXPHOS and substrate level phosphorylation == | ||
[[OXPHOS capacity]], measured as oxygen flux in coupled, ADP- and Pi-saturated mitochondria in an [[Pathway control state|ETS-competent substrate state]], may be limited by the phosphorylation system capacity. Mitochondria are the location of the chemiosmotic DT-system, but additionally carry out substrate-level phosphorylation in the TCA-cycle at the step of [[succinyl-CoA synthase]], phosphorylating GDP to GTP or ADP to ATP (taken together as DT). This step must be considered in the mtDT-phosphorylation system. If succinate is externally added to mt-preparations, succinyl-CoA synthase is not involved. However, if succinate is formed in the mt-matrix from 2-oxoglutarate (alpha-ketoglutarate), substrate-level phosphorylation at succinyl-CoA synthase must be accounted for in the interpretation of P/O (P/O<sub>2</sub>) ratios. | [[OXPHOS capacity]], measured as oxygen flux in coupled, ADP- and Pi-saturated mitochondria in an [[Pathway control state|ETS-competent substrate state]], may be limited by the phosphorylation system capacity. Mitochondria are the location of the chemiosmotic DT-system, but additionally carry out substrate-level phosphorylation in the TCA-cycle at the step of [[succinyl-CoA synthase]], phosphorylating GDP to GTP or ADP to ATP (taken together as DT). This step must be considered in the mtDT-phosphorylation system. If succinate is externally added to mt-preparations, succinyl-CoA synthase is not involved. However, if succinate is formed in the mt-matrix from 2-oxoglutarate (alpha-ketoglutarate), substrate-level phosphorylation at succinyl-CoA synthase must be accounted for in the interpretation of P/O (P/O<sub>2</sub>) ratios. | ||
Revision as of 12:29, 8 November 2016
- high-resolution terminology - matching measurements at high-resolution
Phosphorylation pathway
Description
The phosphorylation system is the functional unit utilizing the protonmotive force to phosphorylate ADP (D) to ATP (T), and may be defined more specifically as the DT-phosphorylation system or DT-system. The DT-system consists of adenylate nucleotide translocase, phosphate carrier, and ATP synthase. Mitochondrial adenylate kinase, mt-creatine kinase and mt-hexokinase constitute extended components of the DT-phosphorylation system, controlling local AMP and ADP concentrations and forming metabolic channels. Since substrate-level phosphorylation is involved in the TCA-cycle, the mtDT system includes succinyl-CoA synthase (GDP to GTP or ADP to ATP).
Abbreviation: DT
Reference: Gnaiger 2009 Int J Biochem Cell Biol
MitoPedia concepts:
MiP concept,
SUIT concept
MitoPedia topics:
Enzyme
Communicated by Gnaiger E 2010-08-15, edited 2016-08-26.
OXPHOS and substrate level phosphorylation
OXPHOS capacity, measured as oxygen flux in coupled, ADP- and Pi-saturated mitochondria in an ETS-competent substrate state, may be limited by the phosphorylation system capacity. Mitochondria are the location of the chemiosmotic DT-system, but additionally carry out substrate-level phosphorylation in the TCA-cycle at the step of succinyl-CoA synthase, phosphorylating GDP to GTP or ADP to ATP (taken together as DT). This step must be considered in the mtDT-phosphorylation system. If succinate is externally added to mt-preparations, succinyl-CoA synthase is not involved. However, if succinate is formed in the mt-matrix from 2-oxoglutarate (alpha-ketoglutarate), substrate-level phosphorylation at succinyl-CoA synthase must be accounted for in the interpretation of P/O (P/O2) ratios.
