Homopantothenic acid

Figure 12.1. Pantothenic acid and reiated compounds and coenzyme A. Relative molecular masses (Mr) pantothenic acid, 219.2 (calcium dipantothenate, 476.5) pantothenol, 214.2 t)-methyl pantothenic acid, 213.6 homopantothenic acid, 233.2 and coenzyme A, 767.6. CoASH, free coenzyme A GABA, y-aminohutyric acid.

Homopantothenic acid, which is not a coenzyme A precursor, did not exert a protective effect against reactive oxygen species (Slyshenov et al. 1995). Slyshenov et al. (1995, 1995, 1998, 1999) therefore proposed that the observed protective effects of pantothenic acid and some of its derivatives against cell and tissue injury may be due to stimulation of biosynthesis of coenzyme A and glutathione. 

Y Umeno, K Nakai, E Matsushima, T Marunaka. Gas chromatographic-mass frag-mentographic determination of homopantothenic acid in plasma. J Chromatogr 226 333-339, 1981. 

AG Moiseenok, VM Kopelevich, MA Izraeht, LM Smuilovich. D-homopantothenic acid, its physicochemical and pharmaceutical properties, metabolism and chnical use. Farmakol Toksikol (Moscow) 36 489-494, 1973. 

Pantothenic acid can be accompanied by its biologically active higher homologue known as homopantothenic acid (5-71), which contains 4-aminobutanoic acid (y-aminobutyric acid) instead of P-alanine and acts as an antagonist of pantothenic acid. 

It is known that homopantothenic acid improves the metabohsm of glucose in the brain and the higher functions of the brain and it has been used in Japan to enhance mental functions, especially in Alzheimer s disease. A rare side-effect is an abnormal brain function resulting from the failure of the liver to eliminate toxins (hepatic encephalopathy). This condition was reversed by pantothenic acid supplementation, suggesting that it was due to pantothenic acid deficiency caused by the antagonist homopantothenic acid. 

The pantothenic acid content in wheat flour is strongly influenced by the degree of milling. There is a higher vitamin level in whole-grain flour, cereal products and legumes, whilst about ten times lower vitamin content is typically found in fruits and vegetables. Homopantothenic acid occurs in cooked rice at concentrations of about 20 mg/kg. 

Similarly to the other B group vitamins, relatively large amounts of pantothenic acid are found in yeasts. Homopantothenic acid occurs in dried yeasts in a concentration of 8500 mg/kg. 

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