W10 The chemistry of vitamins ll

Question 1

What are the fat-soluble vitamins?

Answer 1

A D E K
(All dogs Eat Kibble)

Question 2

What are the water-soluble vitamins?

Answer 2

B and C
B1, B2, B3, B5, B7, B9, B12

Question 3

What are the 8 vitamin B?

Answer 3

B1- Thiamin
B2- Riboflavin
B3- Niacine amide
B5- Pantothenic acid
B6- Pyroxidine
B7-Biotin
B9- Folic acid
B12- Cobalamin

Question 4

Vitamin B1 – Thiamin(e)
What do the deficiences include?

Answer 4

• Essential Micronutrient
• Deficiencies include:
  -Beriberi
  -Wernicke-Korsakoff Syndrome
  -Optic Neuropathy
  -Leigh’s Disease
• Available in many whole grains and legumes but due to processing much of this is often removed so need to fortify flour / cereals
• 5 natural thiamine phosphate derivatives involved in many cellular processes
• We will focus on Thiamine Pyrophosphate

Question 5

Thiamine Pyrophosphate / Thiamine Diphosphate
Participates as a coenzyme in metabolic reactions
What is a coenzyme?

Answer 5

A cofactor loosely bound to the active site of enzymes to aid with their functioning. They are freely diffusing organic compounds that can promote metabolic reactions.

Question 6

Thiamine Pyrophosphate / Thiamine Diphosphate
-Acts as an electron sink to stabilise carbanion intermediates

What is an electron sink?
What is a carbanion?

Answer 6

Electron sink: New bonds or lone pairs of electrons can be accepted.

Carbanion:
* Organic ions which contain a negatively charged carbon atom are called as Carbanions.
* It is a negatively charged carbon atom having eight electrons in its outermost shell or valence shell.
* Generally, it undergoes sp3 hybridisation.

Question 7

Thiamine Pyrophosphate / Thiamine Diphosphate

Answer 7

• Participates as a coenzyme in metabolic reactions
• Acts as an electron sink to stabilise carbanion intermediates
• The thiazole ring is the most important part (from a catalytic standpoint)
• The proton on the carbon between nitrogen and sulfur on the thiazole ring is weakly acidic (pKa = 18)
• What type of molecule would we form if we deprotonated this thiazole ring?
  = Ylide

Question 8

Thiamine Pyrophosphate / Thiamine Diphosphate
Reaction:

Answer 8

• Ylides = Nucleophilic
• Step 1 of Thiamine Pyrophosphate (TPP) reactions is nucleophilic attack of Ylide on carbonyl of substrate
• TPP assists in breaking bonds next to a ketone or aldehyde
• Decarboxylation
• Mechanism of action (pyruvate decarboxylase with TPP)

Question 9

Vitamin B2 - Riboflavin:
What is it essential for?

Answer 9

• Essential for the formation of 2 coenzymes (flavin mononucleotide, flavin adenine dinucleotide (FAD))
• These coenzymes are involved in metabolism, cellular respiration and antibody production.
• Deficiency is rare but the coenzymes support the function of 70+ flavoenzymes in human that are responsible for redox reactions.

Question 10

Redox Reactions
What are the oxidation numbers for free elements, monoatomic ions, Alkali Metals and Alkali Earth Metals, fluorine, hydrogen, oxygen, other halogens, sum of oxidation numbers.

Answer 10

Some species undergo oxidation (loss of electrons) and others undergo reduction (gain of electrons)
- OILRIG

Oxidation numbers:
Free Elements = 0
Monatomic ions= number equal to its charge.
Alkali Metals and Alkali Earth Metals= +1/ +2
Fluorine= -1
Hydrogen= +1
Oxygen= -2
Other Halogens= -1
Sum of Oxidation Numbers = 0

refer to ppt

Question 11

Whats the oxidation number of each atom in SF6

Answer 11

F is -1 x 6 so -6
and that means S is +6
F= -1
S= +6

Question 12

Whats the oxidation number of each atom in H3PO4?

Answer 12

H = +1 x 3 = +3
O is -2 x 4 = -8
so P= +5

H= +1
P= +5
O= -2

Question 13

Whats the oxidation number of each atom in IO3-?

Answer 13

O= -2x3 = -6
there is a - charge so -5
I is +5

I= +5
O= -2

Question 14

Vitamin B3 - Niacin

Answer 14

• Vitamin family (3 members)
• nicotinic acid, nicotinic ribosamide, niacinimide (nicotinamide)
• Niacin can be produced from tryptophan by plants and animals
• Nicotinamide is a component of coenzymes Nicotinamide Adenine Dinucleotide (NAP) and Nicotinamide Adenine Dinucleotide Phosphate (NADP+)

Question 15

Vitamin B5 – Pantothenic Acid
Is it a common vitamin?
What is it a combination of? (2)
What is it essential to produce?

Answer 15

• Pantothenic acid is named from the Greek word “pantothen” meaning “everywhere” as pantothenic acid is almost all foods
• It is a combination of pantoic acid and β-alanine
• All animals need it to sythesise coenzyme A (CoA) which is essential for fatty acid synthesis, energy production, glucose regulation and as an antioxidant

Question 16

Vitamin B6:
What is it needed for?

Answer 16

• 6 chemically similar compounds make up the B6 family
• Pyridoxal 5’-phosphate is the active form
• Needed for amino acid metabolism, biosynthesis of neurotransmitters, glucose and lipid metabolism and haemoglobin synthesis
• Is sometimes co-administered with isoniazid (TB) to alleviate numbness

Question 17

Vitamin B7 - Biotin
What is it Marketed in the US for?

Answer 17

• Has also been known as Vitamin H
• Involved in a range of metabolic processes (primarily as a cofactor for enzymes)
• Deficiency is rare and mild – skin rash (usually on face), thinning hair and brittle nails
• Marketed in the US to strengthen hair and nails however these products all must have a disclaimer that it is not verified
• If you are interested there is some research in recent years into Biotin being used to treat multiple sclerosis

Question 18

Vitamin B9 – Folic Acid:

Answer 18

• A member of the folate family
• Required for metabolism, cell division, RNA and DNA synthesis
• Deficiency: Neural Tube Defects (NTDs), Anaemia, various cancers, stroke
• Mandatory fortification of wheat flour: Australia, New Zealand, Canada, USA
• Not mandatory: UK
• Folic acid must be converted to tetrahydrofolic acid (TFA) to be active

Question 19

Vitamin B12 - Cobalamin:
What is it required for?

Answer 19

• Coordination complex of Cobalt
• DNA synthesis, fatty acid and amino acid metabolism, myelin synthesis, maturation of RBC in bone marrow.
• Wide range of symptoms and illnesses from deficiency – Anaemia may be most prominent
• Hydroxycobalamin given intravenously to treat cyanide poisoning
• Cyanide exchanged with OH and trapped by the cobalt and then is excreted via urine

Question 20

Vitamin C – Ascorbic Acid
Medical uses?
Vitamin C relates to which enantiomer??

Answer 20

• Probably the most well-known Vitamin
• Medical uses include: Scurvy, Common cold (immune system regulation), iron deficiency, brain function (including AD and dementia)
• No evidence to support: Cancer treatment or prevention, cardiovascular disease risk, skin ageing, rheumatoid arthritis
• Vitamin C always refers to L-enantiomers of ascorbic acid and its oxidised forms
• Structurally related to glucose.

Question 21

Fischer Projections:

Answer 21

Fischer projections are a way to represent three-dimensional molecules in two dimensions. By following specific rules for drawing these projections, one can depict complex carbohydrates such as glucose and fructose in a way that conveys their structural information.