Nutrition- Vitamin B6

Front 1

What is the generic descriptor of Vitamin B6?

Back 1

Is the generic descriptor for all 3-hydroxy-2-methylpyridine derivatives exhibiting qualitatively the biologicalactivity of pyridoxine (3-hydroxy-4, 5-bis (hydroxymethyl)-2-methylpyridine).

Front 2

How many vitamers does Vitamin B6 have and what are they?

Back 2

Vitamin B6 exists as six vitamers:

Pyridoxamine (the amine form).

Pyridoxal (the aldehyde form).

Pyridoxine or Pyridoxol (the alcohol form)

All of each having a 5’-phosphate derivative.

Front 3

Are these vitamers interchangeable?

Back 3

These vitamers are interchangeable, comparably active (same biological activity from all of them), and function as co-enzymes for multiple reactions (>100), mostly involved in amino acid metabolism.

Front 4

What happens if you do not have Vitamin B6?

Back 4

In fact, without Vitamin B6, non-essential amino acids become essential and need to be obtained from the diet.

Front 5

Why does non-essential aa become essential aa if you do not have vitamin B6?

Back 5

This is because in the absence/deficiency of Vitamin B6, means out body cannot make non-essential amino acids.

Front 6

What is Vitamin B6 sometimes referred to as?

Back 6

The Protein Vitamin

Front 7

What is Vitamin B6 resistant to?

What is Vitamin B6 destroyed by?

Back 7

Vitamin B6 is fairly resistant to cooking processes;

However, some losses are expected with prolonged heating and exposure to light or alkaline conditions.

Also refining of cereal grains removes Vitamin B6

Front 8

What is the wheat kernel breakdown of Vitamin B6?

Back 8

Forwheat kernel:

Bran (outer portion): 73% Vitamin B6

Endosperm (middle portion): 6% Vitamin B6 Germ (inner portion): 21% Vitamin B6

Front 9

Where is Vitamin B6 primarily absorbed?

Back 9

Vitamin B6 is primarily absorbed in the jejunum by passive diffusion.

Front 10

Can phosphorylated Vitamin B6 enter into the enterocyte just like nonphosphorylated?

Back 10

No. the phosphorylated vitamers must be dephosphorylated.

Front 11

How are the phosphhorylated vitamers desphosphorylated?

Back 11

By alkaline phosphatase at the intestinal brush border or other intestinal phosphatases to yield Pyridoxine, Pyridoxal, and Pyridoxamine. They then can enter the enterocyte, and are then released into the portal vein.

Front 12

What is the main organ that metabolizes Vitmain B6?

Back 12

Liver.

The liver is the primary organ that metabolizes vitamin B6, which includes its phosphorylation or inter-conversions of the vitamers.

Front 13

In the cell, what is Vitamin B6 bound to?

Back 13

Intracellular Pyridoxal phosphate is bound to specific proteins (binding proteins).

Front 14

In the cell, what happens to unbound Vitamin B6?

Back 14

The unbound fraction is hydrolyzed to Pyridoxal and released into the blood for transport to other tissues.

Front 15

What is the main form of Vitamin B6 in the blood?

Back 15

Pyridoxalphosphate is the main circulating form of the vitamin and most of it is bound to albumin.

Front 16

Which form of Vitamin B6 can enter the cells?

Back 16

Only the non-phosphorylated forms of Vitamin B6 can be up taken by peripheral tissues,so Pyridoxal phosphate is typically hydrolyzed by alkaline phosphatase prior to cellular uptake.

Front 17

What is the main storage of Vitamin B6?

What else takes up Vitamin B6?

Back 17

Muscle is the main compartment for storage of Vitamin B6 (75-85%), whereas the liver stores about 5%.

Brain,kidneys, and spleen also store some Vitamin B6.

Front 18

What happens to Vitamin B6 once inside the tissue?

Back 18

In tissues, vitamin B6 is phosphorylated, which prevents its diffusion out of the cell.

Also,the binding of the vitamin to protein prevents hydrolysis by phosphatases.

Front 19

What are the primary functions of Vitamin B6?

Back 19

Required as enzyme cofactor for carbohydrate and amino acid metabolism.

Acts as a co-enzyme in the first step in the synthesis of heme, therefore, it assists in the synthesis of blood cells.

Front 20

Symptoms of Deficiency of Vitamin B6

Back 20

Anemia,Seborrheic dermatitis, Depression, Confusion, Convolutions

Front 21

Symptoms of Toxicity of Vitamin B6

Back 21

Nerve Damage, Skin Lesions.