to overview Vitamins
Occurrence and structure
Pyridoxine is also very common, especially abundant in liver, pork and chicken, nuts, fish, vegetables and brewer’s yeast. Pyridoxine occurs in various forms, all of which have in common the pyridine ring (contains a nitrogen atom), which is substituted in some places (i.e. to which different groups are attached). Pyridoxal also has an aldehyde group = H-C=O), pyridoxol a hydroxyl group (OH) and pyridoxamine an amino group (NH2). Vitamin B6 is also contained in: Nuts, lentils, lamb’s lettuce, potatoes, whole grain cereals, yeast, cabbage, green beans, whole grain products, wheat germ,
Function
After vitamin B6 has been absorbed, it is activated to pyridoxal phosphate (PALP) by attaching a phosphate group. As such, it is involved in For those interested, here is a brief explanation of the above reactions: In a transamination, an amino group is transferred from an amino acid to an alpha-keto acid. This turns the amino acid into an alpha-keto acid and the alpha-keto acid into an amino acid: Since there is not only one alpha-keto acid and of course numerous amino acids, this reaction makes sense – even if it looks like the same thing is converted into the same thing – so for example pyruvate (keto acid) is formed from alanine (AS) or oxalacetate (keto acid) from aspartate (AS).
However, the most important transamination reaction is that of glutamate (AS) to alpha-ketoglutarate. During decarboxylation, one amino acid usually produces its so-called biogenic amine. It is one C atom shorter and often has the most important functions in the body. Here are a few examples of amino acid and biogenic amine extra to mention the involvement of PALP in the synthesis of heme, which is a part of the hemoglobin of red blood cells.
- Transamination (transfer of NH2 groups from one to the other reactant)
- Decarboxylations (splitting off of C-atoms)
- Deamination (separation of NH2 groups)
- Alpha-keto acid + amino acid à amino acid + alpha-keto acid
- Tryptophan – SerotoninMelatonin
- Glutamate – GABA (gamma-aminobutyric acid)
- Serine – Ethanolamine
- Tyrosine – DOPA (precursor to dopamine, norepinephrine and adrenaline)
