The chemical make up of vitamin B6 has been studied for many years. The isolation of pure crystalline vitamin B6 was first reported in 1935, four years after acknowledgment of this particular member of the vitamin B, complex. Separately, but somewhat later, several other people also accounted for the isolation of vitamin B6. Within a year many experts demonstrated that vitamin B6 was a pyridine derivative, distinctively 3-hydroxyl-4, 5- dihydroxymethyl- 2-methyl- pyridine. The term pyridoxine, used for this compound has become generally accepted (Gyorgy, n.d.).

Over the years many others confirmed that a phosphoric derivative of pyridoxal, later acknowledged as pyridoxal 5'-phosphate (II; R = -CHO), is the coenzyme of a large collection of specific enzymes catalyzing responses of amino-group transport, decarboxylation and other metabolic alterations of individual amino acids. In the route of enzymic transamination, pyridoxal 5'-phosphate undergoes reversible adaptation into pyridoxamine 5'-phosphate (II; R = -CH2NH2), which has coenzyme activity for the aminotransferases (EC 2.6.1.-), but not for other kinds of vitamin B-6-dependent enzymes. In the IUPAC Definitive Rules for the Nomenclature of Vitamins, published in 1960, the term pyridoxine was suggested as a generic description of the B-6 vitamins, and pyridoxol as the minor name for the alcohol form (I; R = -CH2OH) previously known as pyridoxine (Rule V-7). In the IUPAC-IUB Tentative Rules of 1966 for the nomenclature of vitamins and related compounds (Rule M-7.1), it was recommended that the later compound should be known as pyridoxine or pyridoxal (Moss, n.d.).

One unfortunate result of these contradictory proposals, gave rise to defensible condemnation, in the ongoing use of the word pyridoxine in two different senses, as a generic expression for substances with vitamin B-6 action, and as the unimportant name of a specific chemical compound which, is one of the fewer plentiful among the naturally occurring forms of vitamin B-6. A widespread review of the literature has been done on the chemistry and biochemistry of the B-6 vitamins and coenzymes, of their metabolites and of numerous associated synthetic compounds that often display biological action as surrogates for or as rival of the equivalent...

A quantity of trivial and semi-trivial names, sometimes mistaken or unclear, has been created for vitamin B-6 derivatives and analogues, and a number of structures of shortened description for these compounds have been introduced. The abbreviations pyridoxal-P, P-pyridoxal, PLP (the symbol used most frequently), PALP, PalP, PALPO are in use for pyridoxal 5'-phosphate, and comparable shortened structures have been utilized for other affiliates of the collection and their derivatives (Moss, n.d.).
Pyridoxine is comparatively stable to heat, but pyridoxal and pyridoxamine are not. Pasteurization consequently causes milk to lose up to 20% of its vitamin B6 substance. Vitamin B6 is decayed by oxidation and ultraviolet light, and by an alkaline setting. Because of this light sensitivity, vitamin B6 will disappear by half within a few hours from milk that is kept in glass bottles exposed to the sun or intense daylight. Alkalis, such as baking soda, also wipe out pyridoxine. Freezing vegetables causes a decrease of up to 25%, while milling of cereals leads to wastes as elevated as 90%. Cooking losses of processed foods may vary from a few percent to nearly half the vitamin B6 that was initially present (Vitamin B6, 2009).

References

Dietary Supplement Fact Sheet: Vitamin B6. (n.d.). Retrieved October 18, 2010, from Office of Dietary Supplements Web site: http://ods.od.nih.gov/factsheets/vitaminb6.asp

Gyorgy, Paul. (n.d.). The History of Vitamin B6. Retrieved October 18, 2010, from Web site:

http://www.ajcn.org/cgi/reprint/4/4/313.pdf

Harrison, Karl. (2010). Structures of Vitamins. Retrieved October 18, 2010, from Web site:

http://www.3dchem.com/molecules.asp?ID=65

Moss, G.P. (n.d.). Nomenclature for Vitamins B-6 and Related Compounds. Retrieved October

18, 2010, from Web site: http://www.chem.qmul.ac.uk/iupac/misc/B6.html

Vitamin B6. (2009). Retrieved October 18, 2010, from Vitamin Basics Web site:

http://www.vitamin-basics.com/index.php?id=47

Vitamin B6 (Pyridoxine). (2010). Retrieved October 18, 2010, from University of Maryland

Medical Center Web site: http://www.umm.edu/altmed/articles/vitamin-b6-000337.htm