Week 6: Vitamins B1-7

Question 1

What is Beriberi?

Answer 1

Thiamine deficiency

• Weakness
• Pain
• Weight loss

Question 2

Thiamine Deficiency MOA

Answer 2

Pyruvate dehydrogenase

• Pyruvate -> Acetyl-CoA
• PDH can’t bind the acetyl group of pyruvate so pyruvate will accumulate leading to production of lactate

α-ketoglutarate dehydrogenase

• α-ketoglutarate -> succinyl-CoA

Because cant do TCA cycle or ETC then can only do glycolysis and fatigue muscle cramps and pain from build-up of lactate

ATP generation is depressed

Question 3

PDH subunits

Answer 3

E1

Vitamin B1 (Thiamine pyrophosphate) needs to be bound to the enzyme to allow for pyruvate to bind to PDH

E2

transfers to E3

E3

Acetyl-CoA

Question 4

Vitamin B1 AKA

Answer 4

Thiamine Pyrophosphate

Question 5

Vitamin B2 AKA

Answer 5

Riboflavin

Question 6

Vitamin B2 Deficiency

Answer 6

FAD - Flavin Adenine Dinucleotide

• FAD -> FADH2 (redox reactions)
• Succinate dehydrogenase uses FAD

FMN -Flavin Mononucleotide

• FMN -> FMNH2 (redox reactions and e- transport
• Part of ETC so cannot transport e- properly

Pyrvate Dehydrogenase

• FAD is bound to part of E3 complex

Fatigue

Muscle Cramps

Muscle pain

Weakness

Question 7

Vitamin B3 AKA

Answer 7

Niacin

Question 8

Vitamin B3 Deficiency

Answer 8

Pellagra

NAD - Nicotinamide Adenine Dinucleotide

• NAD+ -> NADH2 (redox reactions - energy

NADP - Nicootinamide Adenine Dinucleotide Phosphate

• FMN -> FMNH2 (redox reactions - biosynthesis)

Skin rashes

peeling

flaking

Diarrhea

(Issue with rapidly dividing cells)

Need energy and biosynthetic power (skin cells, epithelial cells)

Question 9

Vitamin B4 AKA

Answer 9

Was a designation given to Adenine, carnitine, or choline

But these are cofactors and not vitamins

Question 10

Vitamin B5 AKA

Answer 10

Pantothenate

Question 11

Vitamin B5 Deficiency

Answer 11

Deficiencies are rare

Synthesis of Co-enzyme A

• necessary in all reactions that involve Co-enzyme A

Can’t make Acetyl-CoA

Would be very severe because we need Acetyl-CoA for everything basically

Question 12

Vitamin B6 AKA

Answer 12

Pyridoxine

Question 13

Vitamin B6 deficiency

Answer 13

• Weakness
• Sleeplessness
• Peripheral neuropathy
• Personality changes
• Dermatitis

Pyridoxine -> pyridoxal-5’-phosphate

problem with Aminotransferases - AKA Transaminases

can’t convert pyridoxamine phosphate to regenerate pyridoxal phosphate

Cant break down AAs for energy (hypoglycemia)

(Hyperammonemia)

Needed for catecholamine synthesis

Synthesis of serotonin and melatonin

Glycogen Phosphorylase

• Cant cleave glucose off of glycogen

Question 14

Vitamin B7 AKA

Answer 14

Biotin

Question 15

Vitamin B7 Deficiency

Answer 15

• Fatigue
• hairloss
• loss of apetite

etc.

Biotin is necessary for carboxylation enzymes (CO2 Donor)

Acetyl-CoA Carboxylase

Acetyl CoA -> malonyl Coa

Pyruvate carboxylase

Pyruvate -> Oxaloacetate

Invovled in 1C transfers (decarboxylation is the CO2 acceptor)

Question 16

Taw egg whites

Answer 16

Cooked egg whites denatures Avidin

Main protein in egg white is ovalbumin

avidin binds to biotin almost irreversible so biotin won’t be biologically available

Lowers affinity for biotin available for gut absorption