Distributed in nature

Latin carbo, charcoal) Carbon, an element of prehistoric discovery, is very widely distributed in nature. It is found in abundance in the sun, stars, comets, and atmospheres of most planets. Carbon in the form of microscopic diamonds is found in some meteorites. 

Sulfur occurs native in the vicinity of volcanos and hot springs. It is widely distributed in nature as iron pyrites, galena, sphalerite, cinnabar, stibnite, gypsum, epsom salts, celestite, barite, etc. 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

Thorium has a wide distribution in nature and is present as a tetravalent oxide in a large number of minerals in minor or trace amounts. Thorium is significantly more common in nature than uranium, having an average content in the earth s cmst of approximately 10 ppm. By comparison, Pb is approximately 16 ppm. Thorium has a seawater concentration of <0.5 x 10 . Thorium refined from ores free of uranium would be almost... 

Benzoic acid in the free state, or in the form of simple derivatives such as salts, esters, and amides, is widely distributed in nature. Gum benzoin (from styrax ben in) may contain as much as 20% benzoic acid in the free state or in combinations easily broken up by heating. Acaroid resin (from anthorrhoca haslilis) contains from 4.5 to 7%. Smaller amounts of the free acid are found in natural products including the scent glands of the beaver, the bark of the black cherry tree, cranberries, pmnes, ripe cloves, and oil of anise seed. Pern and Tolu balsams contain benzyl benzoate the latter contains free benzoic acid as well. The urine of herbivorous animals contains a small proportion of the glycine derivative of benzoic acid, hippuric acid [495-69-2] (CgH CONHCH2COOH). So-called natural benzoic acid is not known to be available as an item of commerce. 

Aromatic six-membered heteroeyeles, isoeleetronie with benzene, are widely distributed in nature, and in the world of synthetie ehemistry. Sinee and C are isoeleetronie, the simplest and most direet hetero-analogue of benzene (1) is the pyridinium ion (2). Further azonia substitution of this kind is theoretieally possible, but knowledge of this type of strueture does not extend beyond the disubstituted speeies (3)-(5). 

Copper (II), Bismuth (III) and lead (II), ai e important elements in the environment and they have essential roles in different biologieal systems. Lead is widely distributed in nature and exhibits severe deleterious effeets on human [1]. Copper is an essential element for the normal metabolism of many living organisms. Bismuth has been used in medieines for the treatment of helieobaeter pylorie-indueed gastritis [2, 3]. Therefore traee analysis of these elements is important for monitoring their eoneentration in the environment. 

Cellulose is the most abundant of naturally occurring organic compounds for, as the chief constituent of the eell walls of higher plants, it comprises at least one-third of the vegetable matter of the world. The cellulose eontent of such vegetable matter varies from plant to plant. For example, oven-dried cotton contains about 90% cellulose, while an average wood has about 50%. The balance is composed of lignin, polysaccharides other than cellulose and minor amounts of resins, proteins and mineral matter. In spite of its wide distribution in nature, cellulose for chemical purposes is derived commerically from only two sources, cotton linters and wood pulp. 

Proteins that contain heme (hemoproteins) are widely distributed in nature. Examples of their importance in humans and animals are listed in Table 32-1. 

In striated muscle, there are two other proteins that are minor in terms of their mass but important in terms of their function. Tropomyosin is a fibrous molecule that consists of two chains, alpha and beta, that attach to F-actin in the groove between its filaments (Figure 49-3). Tropomyosin is present in all muscular and muscle-fike structures. The troponin complex is unique to striated muscle and consists of three polypeptides. Troponin T (TpT) binds to tropomyosin as well as to the other two troponin components. Troponin I (Tpl) inhibits the F-actin-myosin interaction and also binds to the other components of troponin. Troponin C (TpC) is a calcium-binding polypeptide that is structurally and functionally analogous to calmodulin, an important calcium-binding protein widely distributed in nature. Four molecules of calcium ion are bound per molecule of troponin C or calmodulin, and both molecules have a molecular mass of 17 kDa. 

As for anthocyanins, betalains are found in vacuoles and cytosols of plant cells. From the various natural sources of betalains, beetroot (Beta vulgaris) and prickly pear cactus (Opuntia ficus indica) are the only edible sources of these compounds. In the food industry, betalains are less commonly used as natural colorants from plant sources than anthocyanins and carotenoids, probably related to their more restricted distribution in nature. To date, red beetroot is the only betalain source exploited for use as a natural food coloring agent. The major betalain in red beetroot is betanin (or betanidin 5-0-P-glucoside). Prickly pear fruits contain mainly (purple-red) betanin and (yellow-orange) indicaxanthin and the color of these fruits is directly related to the betanin-to-indicaxanthin ratio (99 to 1, 1 to 8, and 2 to 1, respectively in white, yellow, and red fruits)." ... 

Astaxanthin (3,3-dihydroxy-p,p-carotene-4,4-dione) is widely distributed in Nature and is the principal pigment in crustaceans and sahnonids. The carotenoid imparts distinctive orange-red coloration to the animals and contributes to consumer appeal in the market place. 

NADH. The enzymes are widely distributed in nature, being found in microorganisms, plants, and animals. Catalytic mechanism, specificity, and physical properties of the alcohol dehydrogenases have been reviewed in detail (91-93). 

Copper oxidases are widely distributed in nature, and enzymes from plants, microbes, and mammals have been characterized (104,105). The blue copper oxidases, which include laccases, ascorbate oxidases, and ceruloplasmin, are of particular interest in alkaloid transformations. The principle differences in specificity of these copper oxidases are due to the protein structures as well as to the distribution and environment of copper(II) ions within the enzymes (106). While an in vivo role in metabolism of alkaloids has not been established for these enzymes, copper oxidases have been used in vitro for various alkaloid transformations. 

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