COURSE TITLE: BIOCHEMISTRY 1 COURSE CODE: BCHT 201 PLACEMENT/YEAR/LEVEL: 2nd Year/Level 4, 1st Semester M.F.Ullah, Ph.D Showket H.Bhat, PhD

VITAMINS  History of vitamins :  The story of vitamin dates back to 18 th century.  In 1912, Sir H.G. Hopkins first identified Vitamins in MILK and named it as Accessory factors.  Funk named the accessory factors as Vitamins (Vital amines).

 Vitamins are micronutrients, which are essential for growth and metabolism.  Non-caloric organic nutrients (Do not provide energy)  Needed in very small amounts but essential so must be supplied through diet except those which are not essential dietary vitamins as can be synthesized by the intestinal bacteria (vitamin K) or by sunlight (vitamin D)  Facilitators – Participate in the physiologigal processes facilitating biochemical pathways for digestion, absorption, metabolism, growth etc.  Some appear in food as precursors called as provitamins What are vitamins: Basic definition

 Vitamins are classified into two types – based on their solubility.  Water soluble vitamins & Fat soluble vitamins. Water soluble Vitamins - Vitamin ‘B’ complex and Vitamin ‘C’ Fat soluble vitamins - Vitamin A, Vitamin D, Vitamin E and Vitamin K Classification

Water soluble vitamins  Water soluble vitamins ◦ Found in vegetables, fruit & grains, meat. ◦ Absorbed directly into the blood stream ◦ Not stored in the body and toxicity is rare.  Vitamin B Complex is a group of water soluble vitamins.  It contains –  a) Thiamine – B1e) Cyanocobalamin – B12  b) Riboflavin – B2 f) Folic acid  c) Niacin - B3 g) Pantothenic acid  d) Pyridoxine – B6 h) Biotin

Mode of action – Vitamins of B complex series act as constituents of coenzymes that are necessary for the proper activity of enzymes. Coenzymes are small organic molecules that link to enzymes and whose presence is essential to the activity of those enzymes. They bind to the active site of the enzyme and participate in catalysis without being transformed (changed) at the end of the reaction.participate in catalysis coenzymes often function as intermediate carriers of electrons, specific atoms or functional groups that are transferred in the overall reaction. VITAMINS AND COENZYMES VitaminCoenzymeReaction type B 1 (Thiamine)TPPOxidative decarboxylation B 2 (Riboflavin)FADOxidation/Reduction (Pantothenate)CoA - Coenzyme AAcyl group transfer B 6 (Pyridoxine)PLP Transfer of groups to and from amino acids B 12 (Cobalamin) 5-deoxyadenosyl cobalamin Intramolecular rearrangements Niacin( B 3 )NAD + Oxidation/Reduction Folic acidTetrahydrofolateOne carbon group transfer Biotin Carboxylation

Compounds Active site Enzyme Without the coenzyme, compounds A and B don’t respond to the enzyme. A B With the coenzyme in place, compounds A and B are attracted to the active site on the enzyme, and they react. Enzyme A B Vitamin Coenzyme The reaction is completed with the formation of a new product. In this case, the product is AB. Enzyme A B The product AB is released. New product A B

Muscles and other tissues metabolize protein. Brain and other tissues metabolize carbohydrates. Bone tissues make new blood cells. Liver and other tissues metabolize fat. Digestive tract lining replaces its cells. Thiamine pyrophosphateThiamine pyrophosphate((TPP) Flavin adenine dinucleotide (FAD) Nicotinamide adenine dinucleotide (NAD + ) Flavin mononucleotide (FMN) Pyridoxal phosphatePyridoxal phosphate (PLP) Tetrahydrofolic acid Tetrahydrofolic acid (THF) Coenzyme A (CoA)

 Deficiency disease - Beri-Beri.  In this disease, the calf muscles become tender, vomiting, tremors, convulsions, loss of appetite are seen.  Sources: Cereals like wheat, oil seeds like groundnut, milk, meat, fish. Thiamine or thiamin or vitamin B 1, named as the "thio-vitamine" ("sulfur-containing vitamin") is a water-soluble vitamin of the B complex. vitamin B complex Its phosphate derivatives are involved in many cellular processes. The best-characterized form is thiamine pyrophosphate(TPP), a coenzyme in the catabolism of sugars and amino acids. phosphate thiamine pyrophosphate coenzyme catabolism sugars amino acids Thiamine is used in the biosynthesis of the neurotransmitter acetylcholine and gamma- aminobutyric acid (GABA). In yeast, TPP is also required in the first step of alcoholic fermentation. neurotransmitter acetylcholine gamma- aminobutyric acidyeast alcoholic fermentation All living organisms use thiamine in their biochemistry, but it is synthesized only in bacteria,fungi, and plants. Animals must obtain it from their diet, and thus, for them, it is an essential nutrient. bacteriafungi plants Animals essential nutrient

 Functions: Riboflavin is essential for oxidation reduction reactions in the cell. vitamin B 2 is required for a wide variety of cellular processes. It plays a key role in energy metabolism, and for the metabolism of fats, ketone bodies, carbohydrates, and proteins.metabolismfatsketone bodiescarbohydratesproteins  Sources: It is present in milk, eggs, liver, kidney and green leafy vegetables.  Deficiency disorders: Deficiency of riboflavin result in Glossitis  Mouth cracks at corners. Photophobia, scaly skin and watering of eyes are some of the symptoms. Riboflavin, also known as vitamin B 2 is an easily absorbed colored micronutrient micronutrient It is the central component of the cofactors FAD and FMN, and is therefore required by all flavoproteins.cofactorsFADFMNflavoproteins The name "riboflavin" comes from "ribose" (the sugar whose reduced form, ribitol, forms part of its structure) and "flavin", the ring-moiety which imparts the yellow color to the oxidized molecule (from Latin flavus, "yellow").ribosereducedribitolflavin

 Niacin is one of the ‘B’ Complex Vitamins. It is also known as Vitamin B 3.  Functions: Niacin is a precursor to NAD+/NADH and NADP+/NADPH, which play essential metabolic roles in living cells. NAD+/NADHNADP+/NADPHmetabolicliving cells Niacin is involved in both DNA repair, and the production of steroid hormones in the adrenal gland.steroid hormonesadrenal gland Niacin has been used to increase levels of HDL in the blood and has been found to modestly decrease the risk of cardiovascular events in a number of controlled human trials.HDL  Sources: It is present in kidney, liver, meat, poultry fish, legumes and groundnuts.  Deficiency disorders: Deficiency of niacin in diet result a disease called Pellagra. The symptoms of pellagra are diarrhea, dementia (loss of memory) patches on the body when exposed to sunlight. 

 Pyridoxine is otherwise called Vitamin-B 6.  Functions: Pyridoxine plays an important role in the metabolism of amino acids as constituent of cofactor pyridoxal phopshate (PLP) for enzyme amino tranferasesin transamination reactions.  Sources: It is present in milk, liver, meat, egg yolk, fish, cereals, legumes and vegetables.  Deficiency disorders: Deficiency lead to hyper irritability, anaemia, nausea and in children it leads to convulsions.

Folic Acid  Sources: It is present in liver, meat, eggs, milk, fruits, cereals, and leafy vegetables over cooking of food destroys the folic acid  Functions :  Precursor of coenzyme tetrahydrofolate (THF) required in nucleic acid biosynthesis reactions.  Folic acid is required for the synthesis of nucleic acids (DNA and RNA).  It is also required for the development of blood cells in the bone marrow.  Deficiency Symptoms: Its deficiency causes anemia, diarrhoea and decrease in the number of leucocytes.  Cell division in tissues such as intestinal mucosa is affected in folic acid deficiency.

Cyano cobalamin: It is also known as vitamin B 12  Functions: It plays an important role in the metabolism of protein. Sources :  Bacteria present in the intestine synthesize this vitamin and supply to our body.  Liver is the main site of storage of vitamin B 12  Deficiency diseases : Deficiency of this vitamin causes pernicious anemia (Pernicious anemia is a decrease in red blood cells that occurs when the intestines cannot properly absorb vitamin B12 due to loss of pareital cells which secrete intrinisic factor for B12 absorption).

 It is one of the ‘B’ complex vitamins.  Functions: It is required for the metabolism of carbohydrates, proteins and fats.  Sources: The sources of pantothenic acid are fresh vegetables, liver, kidney, yeast, egg yolk, meat, ground nuts etc.  Deficiency leads to burning sensation in feet

Biotin is one among the ‘B’ complex vitamins.  Functions: It is required for carboxylation reactions.  Sources: Biotin is present in pulses, nuts, vegetables, liver and kidney.  Deficiency disorders: Deficiency leads to muscle pains, fatigue, disorders in the nervous system and mental depression.

Vitamin C – It is also called as Ascorbic Acid. Like vitamin B complex vitamin C is also classified as water soluble vitamins  Sources: Vitamin C is present in fresh fruits, green leafy vegetables, tomatoes and germinating pulses.  Citrus fruit and Indian gooseberry are the richest source of this vitamin.  Guava is another cheap and rich source of Vitamin C.  Functions *Vitamin C plays an important role in tissue oxidation reactions (anti-oxidant) *It is required for the formation of collagen which is essential for the formation of blood vessels, connective tissue, cartilage and dentine of teeth. *Vitamin C also helps in the absorption and storage of iron. * Vitamin C is also required for normal growth, tissue repair, healing of wounds and fracture of bone.

Vitamin C deficiency: SCURVY Scurvy is the nutritional disorder caused due to the deficiency of Vitamin ‘C’. The symptoms of this disease are swelling of gums, bleeding from gums and from the joints and under the skin. This disease is preventable by providing the diet that is rich with Vitamin-‘C’.