Vitamins biochemistry

Vitamin biochemistry is a fascinating topic of knowledge. Many of the functions of "the vitamins," as revealed in this chapter, also take place in plants, bacteria, and archae. However, those interesting in delving deeper will be delighted to Icam about further functions of "the vitamins" that take place in these life forms. One of the stranger functions, for example, is the role of folates as a structural component in some bacterial viruses. 

Cobalt (Co) is essential for humans only as an integral part of vitamin (cobalamin). No other function for cobalt in the human body is loiown. Details of vitamin biochemistry and function are discussed above. Microflora of the human intestine cannot use cobalt to synthesize physiologically active cobalamin. The human vitamin B12 requirement must be supplied by the diet. Free (nonvitamin B12) cobalt does not interact with the body vitamin B12 pool. 

J. Ganguly, Biochemistry of Vitamin A, CRC Press, Boca Raton, Fla., 1989. 

Disease States. Rickets is the most common disease associated with vitamin D deficiency. Many other disease states have been shown to be related to vitamin D. These can iavolve a lack of the vitamin, deficient synthesis of the metaboUtes from the vitamin, deficient control mechanisms, or defective organ receptors. The control of calcium and phosphoms is essential ia the maintenance of normal cellular biochemistry, eg, muscle contraction, nerve conduction, and enzyme function. The vitamin D metaboUtes also have a function ia cell proliferation. They iateract with other factors and receptors to regulate gene transcription. 

DeLnca, H., and Schnoes, H., 1983. Vitamin D Recent advances. Annual Review of Biochemistry 52 411—439. 

Problem 14,14 A knowledge of molar absorpiivities is particularly important in biochemistry, where UV spectroscopy can provide an extremely sensitive method of analysis. For example, imagine that you wanted to determine the concentration of vitamin A in a sample. If pure vitamin A has Amax = 325 (e = 50,100), what is the vitamin A i concentration in a sample whose absorbance at 325 nm is A = 0.735 in a cell with 1 a pathlength of 1.00 cm ... 

One major prerequisite for the maintenance of health is that there be optimal dietary intake of a number of chemicals the chief of these are vitamins, certain amino acids, certain fatty acids, various minerals, and water. Because much of the subject matter of both biochemistry and nutrition is concerned with the smdy of various aspects of these chemicals, there is a close relationship between these two sciences. Moreover, more emphasis is being placed on systematic attempts to maintain health and forestall disease, ie, on preventive medicine. Thus, nutritional approaches to—for example—the prevention of atherosclerosis and cancer are receiving increased emphasis. Understanding nutrition depends to a great extent on a knowledge of biochemistry. 

Bender DA Nutritional Biochemistry of the Vitamins. 2nd ed. Cambridge Univ Press, 2003. 

Vitamin E consists of a family of related compounds, the tocopherols. The most abundant in the American diet is 7-tocopherol and, although it is potentially superior in the detoxification of nitrogen dioxide, the biochemistry of a-tocopherol is considered more relevant to cardiovascular disease (Kayden and Traber, 1993). Vitamin E undoubtedly has several modes of action in vim. The most clearly understood of these, at the chemical level, is the role of a-tocopherol as an antioxidant. 

Gross M, Kumar R. 1990. Physiology and biochemistry of vitamin D-dependent calcium binding proteins. Am J Physiol 259 F195-F209. 

The fibroblasts do not convert cyanocobalamin or hydroxocobalamin to methylcobalamin or adenosyl-cobalamin, resulting in diminished activity of both N5-methyltetrahydrofolate homocysteine methyltransferase and methylmalonyl-CoA mutase. Supplementation with hydroxocobalamin rectifies the aberrant biochemistry. The precise nature of the underlying defect remains obscure. Diagnosis should be suspected in a child with homocystinuria, methylmalonic aciduria, megaloblastic anemia, hypomethioninemia and normal blood levels of folate and vitamin B12. A definitive diagnosis requires demonstration of these abnormalities in fibroblasts. Prenatal diagnosis is possible. 

The Chemistry of Polymers by J. W. Nicholson Vitamin C - Its Chemistry and Biochemistry... 

The story related here will clarify, to some extent, the roles of these pioneers in the emergence of the vitamin hypothesis. More importantly, it will shed light on some peculiarities of nutritional biochemistry as it was practiced in the first quarter of the twentieth century. In particular, it will focus upon experimental results that helped one investigator win a Nobel Prize, results that could not be reproduced by some of the most competent research workers in animal feeding experiments. 

In addition to the references after each Chapter, many of the articles in early editions of Annual Reviews of Biochemistry, Advances in Enzymology, Advances in Protein Chemistry, International Reviews of Cytology, Physiological Reviews, Vitamins Hormones, and other review serials, refer to specific topics considered in the text. Most of the articles we have cited give an overview of the topics. Where these are available many individual references have been omitted. 

More than most of us can hope for, Williams life was also filled with extraordinary gifts and accomplishments. For over 20 years he and his co-workers worked to discover, isolate, characterize and synthesize the substance he named pantothenic acid, an essential cog in the biochemical machinery of all living things. He also first concentrated and named folic acid, another B vitamin. As founder and director of the Clayton Foundation Biochemical Institute at the University of Texas at Austin from 1940 to 1963, he and his colleagues made many other notable contributions to nutrition and biochemistry. 

Finally, we come to the last of the vitamins that appear on the contents list of my multivitamin pill—pantothenic acid. This water-soluble vitamin serves a single purpose in physiology and biochemistry it is a precursor to a far more complex molecule known as coenzyme A or, simply, CoASH. 

Department biochemistry of vitamins and co-enzymes, A.V. Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, 9 Leontovich str., 01601, Kyiv, Ukraine. 

Tor a comprehensive discussion of the reactions and properties of vitamins and cofactors, readers are urged to consult Biochemistry The Chemical Reactions of Living Cells (2nd ed.) by D. E. Metzler (2000) Academic Press, Orlando. This text and reference book contains a valuable compilation of literature citations. 

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