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Showing posts from February, 2012

The Volatile Chemicals

As with many drugs in recreational use, there are feds and fashion in inhalants-substances containing volatile chemicals that have psychoactive (and other) effects when inhaled. In the 1960s, the in substance in this category was model airplane glue. More recently a variety of other substances have been sniffed in quest a quick "high," including gasoline, furniture polish, insecticide, transmissin fluid, paint thinners, and more. All are highly toxic and can cause damage to vital organs such as lungs, kidney, liver and brain, and death. Nitrous Oxide Recreational use of nitrous oxide, discovered in 1773 and first used in dentistry in the 1849s, actually predates its medical use. Still employed as an anesthetic (it is also the propellant in whipped cream dispensers), among the least toxic inhalants. It is toxic, nevertheless, and death can follow if it is inhaled with insufficient oxygen. What happens if a person takes nitrous oxide over a long period? Repeated, long-term

Liquid Ammonia as Solvent

One of the most water-like and certainly one of the most comprehensively studied, of the non-aqueous solvents is liquid ammonia. Early interest in reactions in this medium has been continued until the literature has become extremely voluminous and complex. References already cited shuld be supplemented by the excellent yearly review compiled for the period 1933-1940 under the general guidance of Watt. Solubility in Liquid Ammonia Inasmuch as the solubilities of materials in liquid ammonia are often markedly different from the corresponding solubilities in water and inasmuch as the reaction solute undergo are often functions of their solubilities, a general summary of solubilities is desirable. Perhaps the outstanding difference between ammonia and water is the ability of ammonia to dissolve, without chemical reaction, five metals which are strongly reducing in character. Thus the alkali metals dissolve readily to yield characteristic blue solution from which the free metals can be

Protein Classification According to Solubilities

Protein Classification according to Solubilities Albumin are characterized by being soluble in water and being coagulated on heating. Example are egg albumin, serum albumin, lactalbumin (from milk), and leucosin (from wheat). Globumins are insoluble in water, coagulated by heating, soluble in dilute salt solutions and precipitated when the salt often used. Examples are myosinogen (from muscle), edestin (from hemp seed), ovoglobulin (from egg yolk), serum globulin, amandin (from almonds), legumin (from peas), and excelsin (from Brazil nuts). Glutelins are insoluble in neutral solvents but soluble in dilute acids and alkalies. Example are glutenin (from wheat) and oryzenin (from corn). Alcohol Soluble Proteins (prolamins or gliadins) are soluble in 70 to 80 percent alcohol. Example are gliadin (from wheat), hordain (from barley), and zein (from corn). Fibrous Proteins Histones are soluble in water and insoluble in dilute ammonia. Solutions of other proteins precipitate histones. Th

The Classification of Protein

Classification of Protein According to Gross Structure A. Fibrous Proteins. These are largely insoluble in ordinary aqueous media (salt solutions, acid, etc.). Their molecular weight is high, though this has not been definitely determined. They consist of fibers made up of long linear molecules arranged (roughly) parallel to the fiber axis. They are amorphous (that is noncrystalline) and are capable of being stretched and then released t contact again. Their function is largely one of structure or support. Years ago they were given such names an albunimoids and sclerins. Example of individual members are collagen (from cartillage); myosin (muscle); keratin (hair); fibrin (clot of blood). These proteins are difficult to purity. B. Globular Proteins. These are soluble in aqueous media (salt solutions, acids, bases, or aqueous alcohol). They have been crystallized and have definite molecular weight. They are characterized by their ability to become denatured, which is a molecular diso

The Nature Chemical of Protein

Chemical Nature of the Protein Using the traditional methods of the organic chemist, it can be shown that protein yield a mixture of amino acids when hydrolyzed by acid, alkali or enzymes. Most protein yield some 19 different amino acids. They are all alpha amino acids, and with the exception of glycine, (which contains no asymetric atom), they all belong to the L-series with reference to the alpha-carbon atom. R-C(alpha)H-COOH-NH3 The structure of typical amono acid is given above, R represent some group which determine the particular kind of amino acid in question. In the original protein molecule these amino acids are joined together by bonds between the carboxyl group of one amino acid and the amino group of another, with the splitting off of water. The bond between two amino acides, -CO-NH- is called the peptide bond. When just two amino acids are involved, the resulting compound is called a dipeptide. The availability of an amino and a corboxyl group in the dipeptide m

Protein in Cell

Protein In the Cell Some 15 percent by weight of the total body is made up of protein. The membrane of animal cells represents an insoluble protein complex; the protoplasm contains soluble proteins and cytoplasmic bodies, which are to a large extent, insoluble proteins such as are found associated with mitochondria and microsomes; though microsomes also contain soluble proteins. Insoluble and soluble proteins are found in the nucleus. Protein are found in all living cells, in single celled algae and bacteria and in multicelled man, and in substances known as VIRUSES, which may well represent the borderline between the living and the lifeless. These proteins have many functions; they include maintaining osmotic integrity; storage for some particular element; enzymes, to catalyze, biochemical reactions, hormones to regulate metabolic processes (like insulin); carriage of molecular oxygen (like hemoglobin); the transportation of lipida (like lipoproteins). The complexity of the pro

Stereochemistry

Stereochemistry is the study of the spatial arrangement of atoms in molecules and the effect thereof on the bulk properties and reactions of chemical compounds. In chemistry, Stereochemical principles have become useful tools for determining the structures and for revealing the details of chemical and biochemical reaction pathways. Stereochemistry is a special concern in the areas of biochemistry, biophysics, and drug development as well. On a molecular level, nearly all biochemical processes involve the spatial recognition of one molecule by another, and such recognition serves as the means by which energy structures are built. As early as 1823, Friedrich Wohler and Jusfus Liebig recognized that two chemical compounds might have the same elemental composition yet differ in the order in which the atoms were linked together. It was widely believed, until almost the end of the 1800s, that these criteria alone were enough to define completely a chemical compound. In 1848, however, the F