| Krebs cycle (citric acid cycle) |
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The Krebs cycle plays a major role in converting foodstuffs such as carbohydrates into energy. It is largely a catabolic process, as it breaks down the carboxylic acids into smaller units. The process is involved in the release of chemical energy, some of this energy is lost as heat and some is stored by molecules able to store energy.
The important cycle consists of six chemical reactions, which take place in a repeating loop. These reactions happen inside cellular organelles, known as the mitochondria, the ‘energy factories’, which release hydrogen in every step by breaking carbon bonds in the food molecules. Eventually, the hydrogen released is eventually transferred to another molecule known as ATP. When ATP is broken down by subsequent hydrolysis it yields ADP adenosine diphospate, inorganic phosphate, which fuels almost all cellular functions with fresh energy.
Each step of the Krebs cycle is highlighted by a specific enzyme.
Step 1 Coenzyme A, derivative of pantothenic acid > citrate, citric acid (transporter)
Step 2 Isomerization > isocitrate
Step 3 NAD molecule > alpha-ketoglutarate
Step 4 Coenzyme A, NADH > succinyl-coenzyme A
Step 5 GTP > succinate
Step 6 FAD > fumarate > malate > oxaloacetate
Forming of many molecules of ATP (energy production)
If a nutrient necessary for successful execution of the Krebs cycle is missing, the cycle is interrupted and starts all over. Needless to say, energy may be hampered if nutrients are unavailable for an extended period of time. The creation of toxic oxidants, or free radicals is a major downfall of the Krebs cycle. They are the result of the occasional escape of an electron from the mitochondrial machinery and the incorporation of that electron by molecular oxygen. This aberrant transfer of a single electron to molecular oxygen creates a free radical, which is highly reactive. If not neutralized, it will react and damage critical cellular components, including proteins, lipids and DNA.
Nutrients to support the proper functioning of the cycle are :
Alpha lipoic acid, B-vitamins (esp. pantothenic acid, thiamin), vitamin C, fatty acids, mineral complex, Coenzyme Q10, vitamin E, these nutrients deliver the nutrients necessary for the Krebs cycle to function properly and offset the negative effects of free radicals. A lot of these supplements are antioxidants.
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