Alpha-amino nitrogen

The formol number is checked for authenticity by means of its ratios with proline, ammonia, alpha-amino nitrogen, and amino acid analyses. The malic acid is checked by enzyme and chemical assays. Based on their data, the Subgroup considers the system to be accurate enough to detect a 10% difference between the measured and stated juice concentration. Their data indicate good agreement between six cooperating laboratories. 

H23. HyAnek, J., and CafourkovA, Z., A screening test for the recognition of increased alpha-amino nitrogen excretion in urine. Clin. Chim. Acta 12, 599-601 (1965). 

Wort is the resnlt of enzymatic hydrolysis of the grist that results from the conversion of starch and proteins into solnble and simpler carbohydrates and peptides, respectively (Chapter 14). The most important wort properties are soluble solids or extract yield ( Plato), percent fermentable sngars, viscosity, pH, color, and alpha amino nitrogen (AAN), also known as free amino nitrogen (FAN). The most relevant determination is the wort density at the end of mashing because it allows processors to calculate the efficiency of solnbilizing the available extract. The most practical way is to determine the density as Plato using a pycnometer (ASBC Wort 3 method). The total extract is calculated by the volume of wort recovered x density x Plato. The volume and density measurements must be referenced to 20 C. Another useful assay... 

Before this is closed, a couple of points need be made regarding nomenclature. Older literature uses alpha for the 2-position of the indole ring. Thus, alpha-methyltryptamine, in early literature, refers to the indole-2-methyl, not to a side-chain methyl derivative. Throughout TiHKAL, the numbers are devoted to the indole ring, and the alpha and beta terms to the side-chain. And the use of the letter N refers to the side-chain amino nitrogen atom. The pyrrole nitrogen is the indole position 1. 

Cll. Childs, B., Urinary excretion of free alpha-amino acid nitrogen by normal infants and children. Proc. Soc. Exptl. Biol. Med. 81, 225-226 (1952). 

Figure 10.12 Schematic representation of alpha helix. Hydrogen bonds (dotted) connect carbonyl oxygens (red) to amino nitrogens (blue) four amino-acid units down the chain.

These compounds were synthesized because it was noticed that several competitive inhibitors of the NMDA receptor had alpha-amino carboxylic acid and phosphonic acid functionalities separated by 3-5 carbons. All of the inhibitors shown in Fig. 11.11 have K- values for inhibition of the NMDA receptor of 10 juM or less. In general, nitrogen substituents larger than those shown decrease receptor affinity. In addition, substitution on the second nitrogen decreases affinity. 

The carcinogenicity of dimethylnitrosamine and 4-nitrosomorpholine was reduced by deuterium substitution for hydrogen on carbon atoms alpha to the amino nitrogen.81 82 Consistent with the hypothesis that alpha-carbon oxidation is required for reactive metabolite formation from nitrosamines, there is a substantial primary deuterium isotope effect (ku/kg = 3.8) on the rate of dimethylnitrosamine N-demethylation. 3 Specific deuteration of 3-methylcholanthrene, a potent polycyclic hydrocarbon carcinogen, showed that oxidation of the 1-carbon atom is critical in the tumor-initiating process in mouse skin. ... 

The data suggested that renal clearance of these compounds was relatively unimportant. Alkyl substitution at the amide nitrogen apparently increased total body clearance while similar substitution alpha to the amino nitrogen did not significantly alter this parameter. Introduction of a P-OC3H7 moiety, and caused substantial Increases in total body clearance when compared to tocainide (11). 

Proteins are giant molecules built up by the condensation of a number of comparatively simple alpha amino acids, in which the amino nitrogen is attached to the —CH — group adjacent to the carboxyl radical, e.g. CH3.CH(NH2).C00H (alanine). The simplest of the amino acids is... 

Amino acids are molecules containing an amine group, a carboxylic acid group and a side chain that varies between different amino acids. The key elements of an amino acid are carbon, hydrogen, oxygen, and nitrogen. They are particularly important in biochemistry, where the term usually refers to alpha-amino acids. 

These requirements are adequate only (1) if the body cells have the ability to synthesize the necessary carbon skeletons (alpha-keto acids) to which the amino nitrogen can be attached and (2) if the diet provides enough nitrogen for the synthesis of the nonessential amino acids so that essential amino acids will not be used to supply amino groups for the nonessential amino acids. 

Efforts to raise the alpha-selectivity have been made. Thus nitration of anthraquinone using nitrogen dioxide and ozone has been reported (17). l-Amino-4-bromoanthraquinone-2-sulfonic acid (bromamine acid) [116-81 -4] (8) is the most important intermediate for manufacturing reactive and acid dyes. Bromamine acid is manufactured from l-aminoanthraquinone-2-sulfonic acid [83-62-5] (19) by bromination in aqueous medium (18—20), or in concentrated sulfuric acid (21). l-Aminoanthraquinone-2-sulfonic acid is prepared from l-aminoanthraquinone by sulfonation in an inert, high boiling point organic solvent (22), or in oleum with sodium sulfate (23). 

Proteins are also important nitrogen compounds. They constitute much of the cell materials, and are present in every type of organism known. In humans, muscle tissue, skin, and hair is mostly protein, about half of the dry weight of our bodies. From a chemical point of view, proteins are polymers of amino acids, alpha amine derivatives of carboxylic acids. Only about 20 different amino acids are actually found in proteins. It is the large number of variations in the protein chain, using only these... 

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