Metabolites, primary/secondary

The EDI of phthalates in China, Germany, Taiwan, and US populations are shown in Table 7. The calculation was based on phthalate metabolite (primary and secondary) concentrations, the model of David [137] and the excretion fractions according to various authors [23,28,143,144]. DEHP median values are very close or clearly exceed the TDIs and RfD values (Table 4). The median values for the rest of PAEs are below levels determined to be safe for daily exposures estimated by the US (RfD), the EU and Japan (TDI) (Table 4). However, the upper percentiles of DBP and DEHP urinary metabolite concentrations suggested that for some people, these daily phthalate intakes might be substantially higher than previously assumed and exceed the RfD and TDIs. 

Chemistry Nonpolar secondary metabolites Primary metabolites (carbohydrates, peptides) Most water soluble... 

There are two major classes of natural products primary and secondary metabolites. Primary metabolites are compounds that exist in all organisms and are involved in basal and vital metabolism (e.g., glucose, fatty acids, amino acids, etc.). Secondary metabolites, alkaloids, terpenoids, and flavonoids, are unique to a particular species and vary in their basic structures. Secondary metabolites are usually accumulated, as most of their end metabolites are in plants, but are excreted in animals and microorganisms and some of these are proven to have pharmacological and ecological significance. 

Plants are capable of manipulating organic syntheses from the simple molecules such as carbon dioxide, water and inorganic ions, giving a complex array of natural products. This metabolic activity leads to two classes of metabolites primary metabolites and secondary metabolites [1, 2]. 

Relative Stability of alcohol, primary, secondary and tertiary models for possible cyclic nitrosamine metabolites as proposed in figure 2. All energies are in kcal/mole. 

Methylation is rarely of quantitative importance in the metabolism of xenobiotics. The methyl group is transferred from the nucleotide S-adenosyl-L-methionine (SAM) by means of a methyltransferase. The functional groups that undergo methylation include primary, secondary and tertiary amines, pyridines, phenols, catechols, thiophenols. The aza-heterocycle pyridine is metabolized to the A-methylpyridin-ium ion, which is more toxic than pyridine itself (Figure 33.18). The binding properties of the ionized metabolite are disturbed by the loss of its hydrophobic feature, resulting from the polarity inversion. 

The theory is presented and assumed to be valid for all true types of metabolites, primary as well as secondary. The theory emphasizes the existence of receptors tuned to the metabolites. These concepts are shown to be compatible with currently accepted genetic mechanisms in procaryotes as well as eucaryotes (Appendix 3). The role and demands to natural products chemistry in order to produce results suited to distinguish between different predictions are discussed (Section 3.1). Since stimuli have such an important place in the theory the character of these are presented (Appendix 2). 

The theory of adaptive variance in metabolism (22) states that AH metabolites, primary as well as secondary, aim at the survival of the population or individual, are expressed as the result of stimuli, and are targeted to interact with receptor systems. 

Plants and animals produce an amazingly diverse range of chemicals. Most of these are based on carbon and so the chemistry of carbon came to be known as organic chemistry, i.e. the chemistry of living organisms, the chemistry of life. These chemical products of plants and animals can be classified into primary and secondary metabolites. Primary metabolites are those which are common to all species and can be sub-divided into proteins, carbohydrates, lipids and nucleic acids. These four groups of... 

Demain, A. L. (1999). Metabolites, primary and secondary. In M. C. Flickinger 8c S. C Drew (Eds.), Encyclopedia of bioprocess technology Fermentation. New York Wiley. 

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