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7/29/2019 Pantothenic Acid -
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Panto then ic ac id
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Historical Background
VitB5.
Pantothenic acid. Pantothenate.
1st
discovered at 1919.
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Chemical structure Formula C9H11O5N.Amide between pantoic acid and B-alanine
pantoic acid -alanine
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Characterize by:
Water soluble vitamin.
Appearance: yellow colour, viscous oil.
Un stable to heat, alkali and acid.
Hydrolytic cleavage to:B-alanine and 2-4dihydroxy 3,3 dimethyl
butyrate
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Has two active forms in the
body:
Coenzyme A:
Coenzyme adapted
from cystiene
,pantothenate and
adenosine
triphosphate
Acyl carrier protein:
Its small negatively
charge alpha helical
protein with high
degree of structural
and amino acid
similarity.
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Active forms:
Coenzyme A
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Active forms:
Acyl carrier protein
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VitB5 Sources
Pantosmeans everywhere
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Pharmacokinetics:
In foods, most pantothenic acid is in the form of :CoA oracyl carrier protein (ACP).
For the intestinal cells to absorb this vitamin,
it must be converted into free pantothenic acid.
Within the lumen of the intestine, CoA and ACPare
Hydrolyzed into 4'-phosphopantetheine.
This then dephosphorylated into pantetheine
Pantetheinase, an intestinal enzyme, thenhydrolyzes pantetheine into free pantothenic acid.
http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=3044http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=3044http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=3044http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=3044http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=3044http://www.ask.com/wiki/Acyl_carrier_protein?qsrc=30447/29/2019 Pantothenic Acid -
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Absorption:
The free pantpthenic acid then absorbedby
either:
- active transport (Na dependant).
- passive transport.
According to the concentration.
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Transport:
Carried in the plasma and erythrocyte.
Enter erythrocyte through passive diffusion.
Distributed to different tissues(brain, heart,kidney, liver).
Enter the cell through Na co transport.
Converted again to the tissue form :
CO enzyme A.
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Metabolism
The synthesis of CoA from pantothenate isregulated primarily by pantothenate kinase, an
enzyme that is inhibited by the pathway end
products, CoA and acyl CoA.
Thus CoA production does not reflect the amount
of available pantothenate
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Coenzyme A synthesisPantothenate
pantothenate kinase
4-phosphopantothenate Cyestiene
ppc synthetase
4-phospho -N-pantothenyl cystiene
ppc decarboxylase4- phosphopantetheine
pp Adenyl transferase
Desphosho coA
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Co A: synthesis
1\ Pantothenate is phosphorylated to 4'-phosphopantothenate.
2\ A cysteine is added to 4'-phosphopantothenate
to form 4'-phospho-N-pantothenoylcysteine (PPC).
3\ PPC is decarboxylated to 4phosphopantotheine.
4\ 4'-phosphopantotheine is adenylylated to formdephospho-CoA.
5\ Finally, dephospho-CoA is phosphorylated usingATP to coenzyme A.
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Synthesized from Apo ACP protien
andCo enzyme A
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Excretion:
Excreted in the urine as free pantothenic acid or 4phosphopantethenate.
In the kidney pantothenic acid either:
Reabsorped.
Tubular secretion.
Amount excreted reflect the dietary intake.
Biomarkers detected by radioimmunoassay.
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Function of Vit B5
Metabolic functions.
Other roles.
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Metabolic
function:
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Format ion
o f acetyl
co A.
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Co A : Funct ions
Citric acid cycle: acetyl residues (in the form ofacetyl Co A) are catabolised.
Fatty acid synthesis & oxidation: fatty acids are
both synthesized from and oxidized to acetyl Co
A.
Cholesterol synthesis: Acetyl Co A is the sourceof all carbon atoms in cholesterol.
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Co A : Funct ions
Biosynthesis of acetylcholine:
choline + acetyl Co A cholineacetyltransferaseAcetylcholine + Co A.
Acetylation reactions: e.g. drugs, post-
translational modification of some proteins.
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In mammals the fatty acid synthase
system is a multienzyme polypeptide
complex.
ACP is part of that complex.
ACP: Funct ion
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Other roles:
Pantothenic acid enhance red blood cellproduction and maintain normal haemoglobin
level
Enhance the immune system through regulating
stress hormones
Maintain the heart healthy through :
lower the cholesterol level
maintain normal blood pressure Reduce the acne
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Recent research:
Diabetic ulceration
Diabetic peripheral polyneuropathy
Testicular torsion
Rheumatoid arthritis
Athletes' performance
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Age group Requirements
Age Dosage
Infant (0-6) month 1.7 mg
Infant (7-12) month 1.8 mg
Children(1-3) yrs 2mg
Children (4-8) yrs 3mg
Children (9-13)yrs 4mg
Adult men and women(+14)yrs 5mg
Pregnant women 6mg
Breastfeeding women 7mg
United Kingdom RDA: 6 mg/day
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Deficiency:
Pantothenic acid deficiency is
exceptionally rare and has not been
thoroughly studied.
Patients with digestive problem
In starvation ,malnutrition cases
and
limited volunteer trials.
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Clinical man ifes tat ions :
Fatigue,irratibilty and apathy,dermatitis, alopecia and ulcer
numbness, paresthesia, and
muscle cramps
HYPOGLYCEMIA
Adrenal insufficiency andhepatic encephalopathy
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TreatmentAll symptoms corrected and
reversed with the return of
pantothenic acid,either by :
Food
Or
Synthetic supplementation.
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Supplementation Pantothenol
More stable form of thevitamin and is often foundin multivitamin
supplements Calcium pantothenate
more stable thanpantothenic acid in the
digestive mentation mayimprove oxygen utilizationefficiency and reducelactic acid accumulation inathletes.
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Antagonists:
Methylpantothenic acid.
Desthio-coenzymeA.
Hopantenate.
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Toxicity
no Tolerable Upper Level Intake(UL) has been established for
the vitamin.Toxicity of pantothenic acid is
unlikely
massive doses (e.g., 10 g/day)may only yield mild intestinal
distress
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