Metabolic pathway

Under metabolic pathways ( engl. metabolic pathways ) is the lock or unlock and remodeling processes in the cells. Is the defined sequence of biochemical reactions, mainly catalysed by enzymes. A pathway corresponds to a simple biological process whereby the delimitation of this term is fluid. 1995 Donald Nicholson united all previously known metabolic pathways in his " Metabolic Pathway Chart".

Metabolic pathways according to function

Pathways of cellular respiration

  • Fatty acid oxidation (e.g., α - or β - oxidation)
  • Cori cycle
  • Glycolysis (formal reversal: gluconeogenesis )
  • Anaerobic respiration
  • Citric acid cycle
  • Glyoxylate cycle
  • Respiratory chain ( oxidative phosphorylation)
  • Q- cycle

Other ways

  • Cholesterol biosynthesis
  • Pentose phosphate pathway
  • Porphyrin synthesis (or heme synthesis )
  • Urea cycle
  • Fatty acid synthesis

Metabolic Pathways

Reaction sequences, enter the metabolites and where such can be removed. The ring closure is effected by regeneration or replacement of the starting molecule. The best known example: the citric acid cycle, which converge " hub of metabolism " in the anabolic and catabolic pathways of carbohydrates, proteins and fats. Many of these cycles were named after their discoverers ( name reactions) and thus represent a piece of Biochemistry history.

Calvin cycle

  • Light- independent reaction ( dark reaction ) of photosynthesis, three molecules of CO2 acceptor ribulose -1 ,5- bisphosphate, are regenerated in the five molecules of a C3 - compound (3 -phosphoglycerate )

Citric acid cycle

  • Ultimate biodegradation of a C2 connection ( activated acetate = acetyl -CoA ) to form CO2 and GTP and the reducing equivalents NADH, H and FADH2, which are oxidized in the respiratory chain to form H2O

Cori cycle

  • Ways of glucose metabolism with the participation of liver and skeletal muscle

Urea cycle

  • Ammonia detoxification in the liver by a cycle metabolites between mitochondria and cytosol

Hatch - Slack cycle

  • C4 Dicarboxylatweg two cell types of C4 plants

Lynen cycle (syn. HMG -CoA cycle)

  • Formation of ketone bodies ( acetoacetate and derivatives) in disturbed carbohydrate metabolism (eg diabetes mellitus)

Pentose phosphate

  • And dismantling of pentose phosphates and formation of NADPH. The pentose phosphate cycle plays an important role in the red blood cells.

Q- cycle

  • Cyclic electron flow at complex III of the respiratory chain; Doubling the energy yield

Substrate cycle

  • Idle cycle by repeated phosphorylation / dephosphorylation of a metabolite. Regulatory function; possible role in heat generation
Donald Nicholson (biochemist) Q cycle 3-Phosphoglyceric acid Ribulose-1,5-bisphosphate KEGG
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