Search results
Results From The WOW.Com Content Network
The glyoxylate cycle is a variant of the citric acid cycle. [4] It is an anabolic pathway occurring in plants and bacteria utilizing the enzymes isocitrate lyase and malate synthase. Some intermediate steps of the cycle are slightly different from the citric acid cycle; nevertheless oxaloacetate has the same function in both processes. [1]
The reaction it catalyzes is: pyruvate + HCO − 3 + ATP → oxaloacetate + ADP + P. It is an important anaplerotic reaction that creates oxaloacetate from pyruvate. PC contains a biotin prosthetic group [1] and is typically localized to the mitochondria in eukaryotes with exceptions to some fungal species such as Aspergillus nidulans which have a cytosolic PC.
Pyruvate cycling commonly refers to an intracellular loop of spatial movements and chemical transformations involving pyruvate. Spatial movements occur between mitochondria and cytosol and chemical transformations create various Krebs cycle intermediates. In all variants, pyruvate is imported into the mitochondrion for processing through part ...
Overview of the citric acid cycle. The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle) [1] [2] —is a series of biochemical reactions to release the energy stored in nutrients through the oxidation of acetyl-CoA derived from carbohydrates, fats, proteins, and alcohol.
Pyruvate is converted into acetyl-coenzyme A, which is the main input for a series of reactions known as the Krebs cycle (also known as the citric acid cycle or tricarboxylic acid cycle). Pyruvate is also converted to oxaloacetate by an anaplerotic reaction, which replenishes Krebs cycle intermediates; also, the oxaloacetate is used for ...
Pyruvate decarboxylation is the step that connects glycolysis and the Krebs cycle and is regulated by the pyruvate dehydrogenase complex when blood glucose levels are high. [9] Otherwise, fatty acid β-oxidation occurs, and acetyl-CoA is required to generate ATP through the Krebs cycle. [ 10 ]
As PEPCK acts at the junction between glycolysis and the Krebs cycle, it causes decarboxylation of a C 4 molecule, creating a C 3 molecule. As the first committed step in gluconeogenesis, PEPCK decarboxylates and phosphorylates oxaloacetate (OAA) for its conversion to PEP, when GTP is present.
The resulting Pyruvate is transaminated to alanine, diffusing to the mesophyll. Alanine is finally transaminated to pyruvate (PYR) which can be regenerated to PEP by PPDK in the mesophyll chloroplasts. This cycle bypasses the reaction of malate dehydrogenase in the mesophyll and therefore does not transfer reducing equivalents to the bundle sheath.