Bacteria vitamin

Owing to the ubiquitous natural occurrence of vitamin K and its production by intestinal bacteria, vitamin K deficiencies are rare. However, they can be caused by certain antibiotics (qv) coupled with a reduced dietary intake. Newborn infants who do not possess the necessary intestinal bacterial population are at danger for vitamin K deficiency. As a result, vitamin K injections are routinely given to the newborn. 

I Newborn Rare In adults Bleeding Rare Vitamin K produced by intestinal bacteria. Vitamin K deficiency common in newborns 1 Parenteral treatment with the vitamin K 1 la recommended at birth 1... 

Vitamin K — Fat-soluble vitamin K is a group name for fat-soluble compounds which have in common a methylated naphthoquinone ring structure. Vitamin K is found in nature in two forms - Ki or phylloquinone is found in plants and vitamin K2 or menaquinone can be synthesized by many bacteria. Vitamin K3 (menadione) is a synthetic form of this vitamin. Vitamin K is used... 

Vitamin B12 (cyanocobalamin) is produced by bacteria vitamin B12 generated in the colon, however, is unavailable for absorption. Liver, meat, fish, and milk products are rich sources of the vitamin. The minimal requirement is about 1 pg/day. Enteral absorption of vitamin B12 requires the so-called intrinsic factor from parietal cells of the... 

Begley TP, Kinsland C, and Strauss E (2001) The biosynthesis of coenzyme A in bacteria. Vitamins and Hormones 61, 157-71. 

In some bacteria, vitamin B12 can be replaced in the culture medium by deoxyribosides, thus suggesting that vitamin Bi 2 plays a role in the conversion of ribose to deoxyribose. Diphosphate ribose nucleotide usually serves as the substrate for the enzyme. The 2-hydroxyl group of the ribose nucleotide is directly replaced by a hydrogen. The exact mechanism of the hydrogen transfer is not known, but it is believed to occur in the form of a hybrid ion, which is derived from a reducing agent. 

In propionic acid bacteria vitamin Bu functions in the isomerization of succinyl-CoA to methylmalonyl-CoA, the key reaction of propionic acid fermentation. This reaction completes the fermentation and the formation of propionic acid as the end product. AdoCbl is also involved in DNA synthesis and in RNR activity there is indirect evidence for the involvement of vitamin in methionine synthesis (Skupin et al., 1970), stabilization of thiol groups in enzymes (Vorobjeva and Iordan, 1976), mediylation of cytosine residues in DNA (Iordan et al., 1979a) and in glutamate mutase activity (Toohey et al, 1961). 

Fermentation is the main pathway of energy transduction in propionic acid bacteria vitamin B -dependent methylmalonyl-CoA mutase catalyzes the interconversion of succinyl-CoA to methylmalonyl-CoA(b). The enzyme is insensitive to thiol reagents. Its molecular weight is 124,000. The enzyme exhibits high affinities to both the coenzyme and substrate the Km values for AdoCbl, for succinyl-CoA and L-methylmalonyl-CoA are 3.5 10 M, 3.45T0 M and 8.0 10 M, respectively. The equilibrium constant, Keq (with succinyl-CoA), is 23.5 (Schneider, 1987). The pH optimum is around 7.4 and the activity is only slightly lower at pH 6.0 and 8.0 (Kellermeyer et al., 1964). 

Vitamin K is required for proper blood clotting. The letter K conies from koagulation, which is German for clotting. Vitamin K is found in the leaves of green plants. Deficiencies are rare because the vitamin is also synthesized by intestinal bacteria. Vitamin KH2 (the hydroquinone of vitamin K) is the coenzyme form of the vitamin. The synthesis of vitamin KH2 is desaibed in Section 19.8. 

Although cobalt ions are found in both the (II) and (III) oxidation states, the most important biological compound of cobalt is vitamin B12 or cobalamin where the Co(III) form is present (256) (Fig. 6.10). Cobalamin or related substances are important biological compounds that are involved in a great variety of activities, particularly in bacteria. Vitamin B12 is also necessary in the nutrition of humans and probably of most animal and plant species. It is of critical importance in the reactions by which residues from carbohydrates, fats and proteins, are used to produce energy in living cells. Pernicious anemia is a severe disease in elderly people. This disease is usually accompanied in mammals by the increased excretion of methylmalonic acid in the urine. Today it is effectively controlled by a 100 /ig injection of vitamin B,2. 

Industrial Application of Acetic Acid Bacteria (Vitamin C and Others)... 

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