Organic compounds amino acids

Sweetness is a quality that defies definition, but whose complexity can be appreciated merely by examining the molecular structures of those compounds that elicit the sensation. They come in all molecular shapes and sizes, and they belong to such seemingly unrelated classes of compounds as aliphatic and aromatic organic compounds, amino acids, peptides and proteins, carbohydrates, complex glycosides, and even certain inorganic salts. 

A7.4.1 Ions, simple organic compounds, amino acids and simple peptides... 

The first studies on the sulfation of organic compounds, amino acids, and proteins have shown that pyridine/sulfur trioxide complex (pyridine/S03 or pyridine/Cl S03H),168-721 concentrated sulfuric acid,173,74 sulfuric acid//V,A -dicyclohexylcarbodiimide,175,761 and chloro-sulfonic acid177 are the most efficient reagents for the sulfation of tyrosine. More recently, alternative methods based on dimethylformamide/sulfur trioxide complex (DMF/S03),152,781 trimethylamine/sulfur trioxide (Me3N/S03),1152,1531 pyridinium acetylsulfate,137,791 and pyr-idinium trifluoroacetylsulfate1801 have been proposed to minimize side reactions which are difficult to control for the chemical sulfation of tyrosine peptides. 

Amino acids As you saw in Chapter 23, many different functional groups are found in organic compounds. Amino acids, as their name implies, are organic molecules that have both an amino group and an acidic carboxyl group. The general structure of an amino acid is shown below. 

Benninghoven, A., Lange, W., Jirikowsky, M., Holtkamp, D. (1982) Investigations on the mechanism of secondary ion formation from organic compounds amino acids. 

Miller found that when mixtures of methane, ammonia, water, and hydrogen were subjected to electric discharges (to simulate lightning), some organic compounds (amino acids, for example) that are important to biology and necessary for life were formed. Similar results have since been... 

The organic solutes shown to be related to stress adaptation include sugars, polyols, tertiary N compounds, amino acids and organic acids. Of particular note are compounds such as proline, glycine betaine and reducing... 

Dietary Reference Intake (DRI) of Cu, 17-18% of the DRI of K, P, and Fe, and between 5 and 13% of the DRI of Zn, Mg, and Mn (Table 5.1). Potatoes are generally not rich in Ca, but can be a valuable source of trace elements, such as Se and I, if fertilized appropriately (Eurola et al., 1989 Poggi et al., 2000 Turakainen et al., 2004 Broadley et al., 2006). Moreover, since potato tubers have relatively high concentrations of organic compounds that stimulate the absorption of mineral micronutrients by humans, such as ascorbate (vitamin C), protein cysteine and various organic and amino acids (USDA, 2006), and low concentrations of compounds that limit their absorption, such as phytate (0.11-0.27% dry matter Frossard et al., 2000 Phillippy et al., 2004) and oxalate (0.03% dry matter Bushway et al., 1984), the bioavailability of mineral elements in potatoes is potentially high. 

Metabolites, vitamins, organic and amino acids, and specialty chemicals are commonly referred to as small molecules, particularly in the therapeutic world to differentiate these compounds from proteins or peptides, commonly named biopharmaceuticals or biologi-cals. Many of the same unit operations are applied for the recovery and purification of small molecules as described above. Purification of bulk products has cost constraints, whereas pharmaceuticals are subject to strict purity requirements. 

Two of these systems, an analyzer for the UV-absorbing constituents (UV-analyzer) and one for carbohydrates, will be discussed in some detail. Two others, one for ninhydrin-positive compounds (amino acids and related compounds) and an analyzer for organic acids, will be introduced as systems that have great potential but which have not been fully developed as yet. These four analytical systems certainly do not represent all the concepts for the use of liquid chromatography in body fluids analysis however, they are systems that have been used at least to some degree in clinical and medical research laboratories. 

A wide variety of products can be produced by fermentation. In some cases the microorganism itself is the product, for example, in the manufacturing of active dry yeast (ADY). Well-known pharmaceutical fermentation products are insulin and penicillin G. Fermentation processes are also used to produce various commodity bioproducts like organic and amino acids, polysaccharides, lipids, chemical compounds like isoprene (Whited et al., 2010), 1,3-propanediol (Nakamura and Whited, 2003), RNA, DNA, enzymes, and other proteins. The large variety of commodity bioproducts produced by fermentation requires an equally large variety of different methods to separate and purify them. Compared to fermentation processes, where usually one unit, the fermenter vessel, is used, several different steps and unit operations are necessary to achieve purification and formulation of bioproducts. 

Nutritional and isotopic studies have shown that the 5-carbon amino acids, glutamic acid, proline, and ornithine, are capable of interconversion and that in different groups of organisms these amino acids do indeed replace each other. In animals the reactions of these compounds... 

Fig. 3.1. Autoradiogram of two dimensional paper chromatogram of 60 minute dark fixation by Bryophyllum calycinum. 1, alanine 2, glutamine 3, asparagine 4, glycine 5, serine 6, glutamate 7, aspartate 8, citrate 9, isocitrate 10, malate 11, fumarate 12, succinate. The main labeled compound is malate. Other metabolically related organic and amino acids also appear. The only products after a 6-s exposure are malic and aspartic acids (data of P.Saltman et al., Plant Physiol. 32, 197-200, 1957, by permission)...

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