TUMS. Vitamins & Coenzymes. Part one. Azin Nowrouzi, PhD. History. Dumas (1871) individuals fed on pure minerals, water, proteins, fats and carbohydrates did not maintain good health. Lunin (1880) similar finding in animals, milk restored them to normal
Azin Nowrouzi, PhD
Casimir Funk, a Polish biochemist, isolated an anti-berberi substance from rice polishing.
Named it vitamine
Vital for life
Originally, it was thought these necessary compounds were all amines. Since they were vital to our health they became known as “vital amines”, ie. vitamines.
When it was discovered that some were not amines, i.e., not ' --ines', the name was changed to: vitamins
Vitamins are micronutrients:
Plants and animals synthesize vitamins.
Thiamine, or thiamin, sometimes called aneurin
Wet beriberi – dilated cardiomyopathy
Due to peripheral dilation of arterioles
Dry beriberi – peripheral neuropathy, atrophy
Alcohol dilated cardiomyopathy
2. Poor growth and "curled toe paralysis" in chicks.
FMN + ATP FAD + ppi
Active coenzymes: nicotinamide-adenine dinucleotide (NAD+)
nicotinamide-adenine dinucleotide phosphate (NADP+).
Both are extremely important in hydrogen transfer reactions catalyzed by dehydrogenase enzymes.
ATP synthesis, from oxidation of primary fuels (glucose, fatty acids and to a lesser extent, amino acids) (NAD+)
Also important in reductive biosynthesis (NADP+)
1. Pellagra in farm animals and humans (fiery inflammation of tongue, mouth and upper esophagus).
2. Poor growth, enteritis and dermatitis.
3. Occurs in people who subsist mainly on corn which is low in both niacin and tryptophan
4. The signs of pellagra include dermatitis, diarrhea, dementia (the three Ds) and loss of tongue papillae.
Sources of B3
Most non-corn-based diets contain adequate amounts of nicotinamide or its precursor, tryptophan.
Adenine is no longer considered a vitamin !
purine (pyrimidine + imidazole)
PAPS (Phosphoadenosine phosphosulfate)
The energy charge can have a value ranging from 0 (all AMP) to 1(all ATP). Most cells maintain EC at a constant value with very little variation: The energy charge of most cells range from 0.8 to 0.95. As EC drops catabolic, energy producing pathways, such as Glycolysis increase in rate, while anabolic, energy consuming pathways decrease in rate. The opposite occurs as EC increases, resulting in a tight control around an optimal value, as seen in the figure. It is evident that control of these pathways has evolved to maintain the energy charge within rather narrow limits. In other words, the energy charge like the pH of a cell is buffered.
lipoic acid = Internal disulfur of 6,8-dithiooctanoic acid.
Lipoic Acid (LA) is part of a redox pair.
PDH = Pyruvate dehydrogenase complex
The reaction is:
Pyruvate + NAD+ +CoASH Acetyl CoA + NADH + H+ + CO2
5 non-protein molecules (coenzymes) required for this enzyme catalyzed reaction are:
NAD+ and CoASH (coenzyme A); (these are present in the equilibrated reaction formula, as can be seen above)
TPP (thiamine pyrophosphate), Lipoic acid and FAD (flavin adenine dinucleotide) participate in the reaction but do not show up in the equilibrated reaction formula.
E1 = Pyruvate dehydrogenase
E2 = Dihydrolipoamide acyltransferase
E3 = Dihydrolipoamide dehydrogenase