Water soluble vitamins Lecture 1 Thiamin & Riboflavin ppt BIOCHEMISTRY
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WATER SOLUBLE VITAMINS
Dr Vijay Marakala M.B.B.S.,M.D
Assistant ProfessorBiochemistry
SIMS&RC
Their common properties are
1. Water solubility.2. Except Vitamin B12 others are not stored.3. Unstable to normal cooking conditions.4. Excreted in urine.
WATER SOLUBLE VITAMINS
• Thiamine [B1]• Riboflavin [B2]• Niacin [B3]• Pantothenic acid [B5] • Pyridoxine [B6]• Biotin • Folic acid• Cobalamine [B12]
Vitamin B complex
WATER SOLUBLE VITAMINS
WATER SOLUBLE VITAMINS
Thiamine Riboflavin
Heat labile sulfur containing vitamin
Contains pyrimidine and thiazole ring
Joined by methylene bridge
It is highly alkaline sensitive
Thiamine
Pyrimidine ring Methylene bridge Thiazole ring
VITAMIN B1 - THIAMINE
Sources
Rich Sources
Good sources
Fair sources
• Outer coatings of food grains like rice, wheat and yeast.
• Whole cereals, pulses, oilseeds and nuts.
• Meat, liver and egg and fish.
Vitamin B1 - Thiamine
VITAMIN B1 - THIAMINE
Thiamine Sources
THIAMINE -RDA
1mg/day
Requirement increases with energy expenditure
Absorption and Transport
It is absorbed in small intestine by active transport mechanism and simple diffusion. Then it reaches liver through circulation.
Ethanol inhibits active transport
VITAMIN B1 - THIAMINE
THIAMINE-ACTIVE FORM
Thiamin pyrophosphate (TPP or TDP) is the active form of
thiamine.
VITAMIN B1 - THIAMINE
Thiamin pyrophosphate (TPP or TDP) is the active form of thiamine.
Functions
VITAMIN B1 - THIAMINE
Essential for release of
energy from carbohydrates
Necessary branched
chain amino acid
metabolism
Needed for normal
functioning of nervous system
In carbohydrate metabolismOxidative decarboxylationTransketolase reactions
VITAMIN B1 - THIAMINE
Pyruvate Acetyl - CoA
NAD+ NADH+H+
Lipoate, CoA-SH, FAD
CO2
Oxidative decarboxylation
VITAMIN B1 - THIAMINE
TPP
PDH
α ketoglutarate Succinyl - CoA
NAD+ NADH+H+
Lipoate, CoA-SH, FAD
CO2
Oxidative decarboxylation
VITAMIN B1 - THIAMINE
TPP
VITAMIN B1 - THIAMINE
Xylose-5 phosphate Ribose-5 phosphate
Glyceraldehyde-3 phosphate Sedoheptulose-7 phosphate
Transketolase TPP
VITAMIN B1 - THIAMINE
VITAMIN B1 - THIAMINE
Thiamine Deficiency:
Failure of carbohydrate metabolism
↓ATP production
Impaired cellular
functions
VITAMIN B1 - THIAMINE
Thiamine Deficiency:
Impaired cellular functions
Neurological symptoms, Edema,
Indigestion,Constipation
VITAMIN B1 - THIAMINE
Thiamine Deficiency:
Neurological symptoms, Edema,
Indigestion,Constipation
BERIBERI
VITAMIN B1 - THIAMINE
Thiamine Deficiency:
Types of BERIBERIDry beriberi
Wet beriberi
Cerebral beriberi
Infantile beriberi
VITAMIN B1 - THIAMINE
WATER SOLUBLE VITAMINS
RIBOFLAVIN
RIBOFLAVIN - CHEMISTRY
It contains heterocyclic isoalloxazine ring and ribitol a sugar alcohol
It is sensitive to light.
RIBOFLAVIN - SOURCES
SourcesMilkCheeseEggsMeat Yeast extractsGreen vegetables
27
VITAMIN B2 -RIBOFLAVIN
RDA
1.3 – 1.7mg/day
VITAMIN B2 -RIBOFLAVIN
Absorption and Transport
Absorbed in small intestine and distributed to all tissues by circulation.
RIBOFLAVIN – ACTIVE FORMS
FMNFAD
RIBOFLAVIN – ACTIVE FORMS
VITAMIN B2 -RIBOFLAVIN
Active forms of riboflavin are FMN and FAD.
They act as prosthetic groups of several enzymes.
Catalyzes oxidation-reduction reactions.
Growth, repair, development of body tissues - healthy skin, eyes and tongue
Functions
VITAMIN B2 -RIBOFLAVIN
Co-enzyme activity
FMN - dependent enzymes
FAD - dependent enzymes
RIBOFLAVIN - DEFICIENCY
Oral
• Angular Stomatitis
• Cheliosis• Glossitis
Facial • Dermatitis of
nasolabial region.
Ocular • Vascularization
of cornea
Riboflavin Deficiency
WATER SOLUBLE VITAMINS
NIACIN
Nicotinic acid Nicotinamide
NIACIN [B3]-CHEMISTRY
NIACIN [B3]- SOURCE
LegumesYeastLiverFish
Meat
Niacin can also be obtained from Tryptophan •
Daily Requirement (RDA):
Niacin [B3]
15-20 mg/day
Absorbed in small intestine and reach various tissues through circulation where they are converted to NAD
and NADP.
Niacin [B3]
Absorption and transport
Niacin [B3]-ACTIVE FORM
NAD+ NADP+
NIACIN [B3]
FUN
CTIO
NS NAD+, NADP+ are involved in oxidation and
reduction reactions
NAD in oxidative pathways- TCA cycle, Glycolysis
NADP in reductive pathways- PPP, Synthesis of cholesterol, FA
NIACIN [B3]
PELLAGRA
Dermatitis
Diarrhoea
Dementia
Death
NIACIN [B3]- DEFICIENCY
CAUSES Dietary deficiency
Deficient synthesis
Isoniazid
Hartnup disease
Carcinoid syndrome
NIACIN [B3]
Niacin Deficiency
WATER SOLUBLE VITAMINS
Pantothenic acid Pyridoxine
Combination of pantoic acid and β-alanine
PANTOTHENIC ACID [B5]-CHEMISTRY
EggLiverMeatYeastMilk
Cereals
PANTOTHENIC ACID [B5]-SOURCES
Daily requirement (RDA)
PANTOTHENIC ACID [B5]
5-10 mg/day.
Absorption and transport
Freely absorbed in the intestine and reach various tissues through circulation.
PANTOTHENIC ACID [B5]
ACTIVE FORMS
Coenzyme-A[CoA-SH]
Acyl carrier protein[ACP]
PANTOTHENIC ACID [B5]
PANTOTHENIC ACID [B5]
Coenzyme A
PANTOTHENIC ACID [B5]
Coenzyme-A
TCA cycle
Fatty acid synthesis
Cholesterol synthesis
ACP
Fatty acid synthesis
PANTOTHENIC ACID [B5]-FUNCTIONS
Rare in humans Burning Foot Syndrome
Experimental animals
AnemiaDermatitisFatty liver
PANTOTHENIC ACID [B5]-Deficiency
:
Time fora short break
1009080706050403020100
••••••••••••••••••••••••••••••••••
PYRIDOXINE [B6]
Pyridoxine
Pyridoxal
Pyridoxamine
PYRIDOXINE [B6]- CHEMISTRY
• Three compounds derived from pyridine show vitamin B6 activity.
PYRIDOXINE [B6]
Whole grainsLegumes
LiverYeastMeat
VegetablesFruits
PYRIDOXINE [B6]
Daily requirement (RDA)
2-2.5 mg/day
PYRIDOXINE [B6]
Pyridoxine is easily absorbed and reaches
various tissues through circulation.
In the tissues pyridoxine is converted to pyridoxal and
pyridoxamine.
Absorption and Transport
PYRIDOXINE [B6]
Active form of vitamin B6
Pyridoxal phosphate
PYRIDOXINE [B6]
PYRIDOXINE [B6]
Protein metabolism
Heme synthesis
Glycogenolysis
PYRIDOXINE [B6]
Transamination
Deamination Decarboxylation
Heme synthesis
Production of Niacin
Glycogenolysis
PYRIDOXINE [B6]
Reaction type Example
Transamination Oxaloacetate + glutamate aspartate + ⇔ α-ketoglutarate
Deamination Serine → pyruvate + NH3
Decarboxylation Histidine → histamine + CO2
Condensation Glycine + succinyl CoA → δ-aminolevulinic acid
PYRIDOXINE [B6]-DEFICIENCY
Microcytic hypochromic anaemia Peripheral neuropathy Convulsions
It is rare in human adults.
Drug induced pyridoxine deficiency
Isoniazid or isonicotinic acid hydrazine (INH)
Pencillamine
Oral contraceptives and excessive alcohol consumption
PYRIDOXINE [B6]
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