Water Soluble Vitamins Flashcards
What are Anti-vitamins? List two:
Anti-vitamins are chemical compounds that inhibit the absorption or actions of vitamins.
Avidin is a protein in egg whites that inhibits the absorption of biotin.
Pyrithiamine is similar to thiamine, vitamin B1, and inhibits the enzymes that use thiamine.
What is the biochemical function of Thiamine?
Thiamine (B1) plays a central role in the generation of energy from carbohydrates. It is involved in RNA and DNA production, as well as nerve function. Its active form is a coenzyme called thiamine pyrophosphate (TPP), which takes part in the conversion of pyruvate to acetyl coenzyme A (CoA) in metabolism.
What is the biochemical function of Riboflavin?
Riboflavin (B2) is involved in the energy production for the electron transport chain, the citric acid cycle, as well as the catabolism of fatty acids (beta oxidation)
What is the biochemical role of Niacin?
What are the two common forms of Niacin?
Niacin (B3) plays an important role in energy transfer reactions in the metabolism of glucose, fat and alcohol.
NAD and NADP
NAD carries hydrogens and their electrons during metabolic reactions, including the pathway from the citric acid cycle to the electron transport chain. NADP is a coenzyme in lipid and nucleic acid synthesis
What is the biochemical role of Pantothenic acid?
What important protein is synthesized from pantothenic acid? What is this protein involved in?
Pantothenic acid is involved in the oxidation of fatty acids and carbohydrates.
Coenzyme A, which can be synthesised from pantothenic acid, is involved in the synthesis of amino acids, fatty acids, ketones, cholesterol, phospholipids, steroid hormones, neurotransmitters (such as acetylcholine), and antibodies.
What is the biochemical role of the active form of pyridoxine?
The active form pyridoxal 5’-phosphate (PLP), serves as a cofactor in many enzyme reactions mainly in amino acid metabolism including biosynthesis of neurotransmitters
Biotin plays a key role in the metabolism of what?
Biotin plays a key role in the metabolism of lipids, proteins and carbohydrates.
Biotin is a critical co-enzyme for what four carboxylases?
Biotin (B7) is a critical co-enzyme of four carboxylases:
1) acetyl CoA carboxylase, which is involved in the synthesis of fatty acids from acetate
2) propionyl CoA carboxylase, involved in gluconeogenesis
3) β-methylcrotonyl CoA carboxylase, involved in the metabolism of leucine
4) pyruvate CoA carboxylase, which is involved in the metabolism of energy, amino acids and cholesterol
Describe the biochemical role of folic acid:
Folic acid (B9) acts as a co-enzyme in the form of tetrahydrofolate (THF), which is involved in the transfer of single-carbon units in the metabolism of nucleic acids and amino acids
THF is involved in pyrimidine nucleotide synthesis, so is needed for normal cell division, especially during pregnancy and infancy, which are times of rapid growth
Folate also aids in erythropoiesis, the production of red blood cells.
Describe the biochemical role of cobalamin:
Cobalamin (B12) is involved in the cellular metabolism of carbohydrates, proteins and lipids.
It is essential in the production of blood cells in bone marrow, and for nerve sheaths and proteins.
Vitamin B12 functions as a co-enzyme in intermediary metabolism for the methionine synthase reaction with methylcobalamin, and the methylmalonyl CoA mutase reaction with adenosylcobalamin
What are the two main biochemical roles of ascorbic acid?
Which one is its main role?
- Acts as an antioxidant, relieving oxidative stress in the body
- is a cofactor for many enzymes, including several collagen synthesis reactions (which when insufficient, causes scurvy)
Most of the function of L-ascorbate as a vitamin relies not on its antioxidant properties, but upon enzymic reactions that are stereospecific.
List all the water soluble vitamins:
B1 (thiamine) B2 (riboflavin, FADH2) B3 (Niacin, NADH) B6 (pyridoxine) B7 (Biotin) B9 (Folic acid) B12 (cobalamins; ex: methylcobalamin, cyanocobalamin) Vitamin C (ascorbic acid)
