The main function of the B-vitamin complex is to assist in the production of energy in the body. They have many vital roles in energy production. Please study Figure -24. You have been seeing pieces of this diagram throughout this chapter. Figure -24 shows all of the B vitamins involved in energy production in one figure.
Many of the important roles of B vitamins take place in tiny organelles called mitochondria, which live deep inside the cells. Energy production in the mitochondria can be thought of in four steps. In each step, bzoenzymes made with B vitamins are essential. These coenzymes are discussed in the text and will be abbreviated below. The key to the enzyme abbreviations is in Figure -24.
STEP 1, BREAKING DOWN BLOOD SUGAR
The first step starts with glycogen, which, as you may recall, is the storage form of glucose, blood sugar. This first step breaks the glycogen down to glucose. This is done with the help of vitamin B6 (PLP). Next, glucose is changed into pyruvate. This is done with the assistance of niacin (NAD). Pyruvate can also be made from certain amino acids with the help of vitamin B6 (PLP).
Figure -24 Energy production and the B vitamins.
STEP 2, THE CENTRAL COENZYME
The second step in energy production produces acetyl-coenzyme A. Pyruvate is made into acetyl-coenzyme A with the help of enzymes made from niacin (NAD) and thiamin (TPP). Acetyl-coenzyme A can also be made from some amino acids with a little help from folate (THF), niacin (NAD), and vitamin B6 (PLP). Vitamin B12 may also be involved in amino acid transformation to ready the amino acids for this step. Fats may be converted to acetyl-coenzyme A with the help of niacin (NADP and NAD), riboflavin (FAD), vitamin B12, and biotin.
STEP 3, THE ENERGY CYCLE
The third step is known as the Krebs cycle or the TCA(TriCarboxylic Acid) cycle. Acetyl-coenzyme A is used to feed the TCA cycle. Pyruvate can skip the second step and move directly to the TCAcycle with the help of biotin. Some amino acids get to the TCAcycle directly using vitamin B6 (PLP). The TCAcycle uses oxygen to produce energy aerobically. Niacin (NAD), thiamin (TPP), and riboflavin (FAD) are needed to keep the cycle running. Thiamin (THF) and vitamin B12 are used to boost other compounds into the TCA cycle. The third step is known as the Krebs cycle or the TCA(TriCarboxylic Acid) cycle. Acetyl-coenzyme A is used to feed the TCA cycle. Pyruvate can skip the second step and move directly to the TCAcycle with the help of biotin. Some amino acids get to the TCAcycle directly using vitamin B6 (PLP). The TCAcycle uses oxygen to produce energy aerobically. Niacin (NAD), thiamin (TPP), and riboflavin (FAD) are needed to keep the cycle running. Thiamin (THF) and vitamin B12 are used to boost other compounds into the TCA cycle.
Adenosine triphosphate (ATP) is the fully charged energy battery of the cell.
STEP 4, PUMPING UP ATP
The fourth step is called the electron transport chain. The electron transport chain pumps up the energy battery of the body, which is known as adenosine triphosphate (ATP). Adenosine monophosphate (mono means one) is pumped up to adenosine diphosphate (di means two), which is then pumped up to adenosine triphosphate (ATP), which has three (tri) phosphates. Adenosine triphosphate (ATP) is the fully charged energy battery of the cells.
The highenergy bonds in ATP that are made in this step are used to produce energy in every cell in the body. Riboflavin (FMN and FAD) and niacin (NAD) play important roles in the electron transport chain, as you can see by reviewing Figure -24. Many other nutrients play important roles in energy production in the cell.
However, the B vitamins are the stars in energy production. The B vitamins work as coenzymes to do their indispensable work.
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