Vitamin B6 are also known as pyridoxine is a water soluble vitamin exist in three forms pyridoxine (the alcoholic form), pyridoxine amine (the amino form) and pyridoxal (the aldehyde form). These forms are interchangeable and comparably active. The interchangeable form of these vitamins are pyridoxine 5 phosphate, pyridoxal 5 phosphate and pyridoxamine 5 phosphate.
DATS (DIGESTION, ABSORPTION,
TRANSPORTATION AND STORAGE) OF VITAMIN-B6 pyridoxine
Sources:
All these vitamins are found in food. Pyridoxine the
stablest form and its phosphorylated form are present mostly in plants in an
conjugated form pyridoxine glycoside. Pyridoxal phosphate and pyridoxal amine
phosphate are mainly found in animals.
Much of the vitamins originally present in food and can be
lost through processing, heating, canning, sterilizing and fewer loses through
storage.
The plant sources of this vitamin include vegetables,
fruits, bananas, nuts, pork, tomato paste.
Animal sources are chicken breast, red meat etc.
Sea sources are sirloin, salmon etc.
RDA (recommended dietary allowances):
The recommended dietary allowances are different for the
individuals of different age groups. RDA for males, females and children are:
Gender |
RDA |
Men |
1.3 micro gram |
Women |
1.3 micro gram |
Children |
2.0 micro gram |
Functions of vitamin B6 in Human
body:
Vitamin B6 performs many important roles in human body these
are:
- it helps in the metabolism of red blood cells, proteins and amino acids.
- It also helps in the conversion of tryptophan to niacin.
- It supports to the healthy immune function.
- It helps in the transportation of selenium.
- It also assist in the metabolism of calcium and magnesium.
DATS (digestion, absorption,
transportation and storage) of vitamin B6:
Digestion:
Prior to be absorbed the phosphorylated form of vitamin B6
must need to be dephosphorylated. Alkaline phosphatases a zinc dependent enzyme
found at the intestinal brush boarders or other intestinal phosphatases are
used to hydrolyze the phosphatase to yield pyridoxine (PN), pyridoxal (PL) and
pyridoxamine (PM).
Absorption:
PL, PN and PM are primarily absorbed in the jejunum by
passive diffusion. At physiological intakes it is absorbed in its free form
directly.
Transportation:
Most of the PL, PN and PM is released unchangeable into the
portal circulation and are taken up by the liver. In liver these vitamins are
primarily converted to PLP. PLP is the main form of vitamin in blood. Other
forms of this vitamin are PL, PN, PM and PMP in blood. In blood it is bound to
albumin in hemoglobin.
Storage:
Liver is the main organ that takes up and metabolizes newly
absorbed vitamins. About 5-10% of this vitamin are absorbed in the liver.
Muscle represents the major storage site of this vitamin i-e about 75-80%. Once
the vitamin move inside the phosphorylation prevents its diffusion out of the
cell. Pyridoxine kinase is used in phosphorylation.
Metabolism Of Vitamin B6 In Liver:
Most of the B6 metabolism occurs in the liver.
Unphosphorylated forms of the vitamers are phosphorylated by a kinase using ATP
within the cytoplasm of the hepatocytes.
The storage form of this vitamin are PLP, PNP and PMP while
its circulatory forms are PN, PM and PL. So prior to its storage
phosphorylation occurs while for transportation DE phosphorylation occurs.
Deficiency:
Deficiency of vitamin B6 leads to microcytic anemia. As
vitamin B6 also helps in the conversion of homocysteine. Its deficiency may
leads to its improper conversion and hyper homocysteine occurs. Impairs niacin
synthesis from tryptophan. It also alters calcium and magnesium metabolism. In
addtition to this glottis, neuropathy and some other complications are also the
cause of vtamin B6 deficiency.
Mechanism Of Action:
For co enzyme action with in a cell, biotin is attached to
four carboxylases:
Pyruvate Carboxylases
The co enzyme form of B6, PLP is associated with a vast
number of enzymes the majority of which are involved in amino acids metabolism.
Some non-coenzyme role of this vitamin effects the action of
steroid hormone and gene expression. Dysfunction of Vitamin B6 appears to
diminish the activity of steroid hormone which in turns diminish the
interaction of nucleoprotein with the DNA.
It also helps in the conversion of glycogen to glucose by
assisting with glycogen phosphorylases.
In process of decarboxylation, transamination, deamination
and other synthetic reactions B6 acts as an enzyme and involves in the transfer
of phosphate group to another.
0 Comments
if you have more queries about this page please let me know