Heterogeneity class

Dietary consumption of polyphenols is associated with a lower risk of degenerative diseases. In particular, protection of serum lipids from oxidation, which is a major step in the development of arteriosclerosis, has been demonstrated. More recently, new avenues have been explored in the capacity of polyphenols to interact with the expression of the human genetic potential. The understanding of the interaction between this heterogeneous class of compounds and cellular responses, due either to their ability to interplay in the cellular antioxidant network or directly to affect gene expression, has increased. 

Quinones represent a very large and heterogeneous class of biomolecules. Three major biosynthetic pathways contribute to the formations of various quinones. The aromatic skeletons of quinones can be synthesized by the polyketide pathway and by the shikimate pathway. The isoprenoid pathways are involved in the biosynthesis of the prenyl chain and in the formation of some benzoquinones and naphthoquinones. ... 

MAb-based constructs represent, as described, a heterogeneous class of anti-tumour agents with remarkable efficacy in the treatment of experimental cancers in animals. Several MAb and immunoconjugates have been evaluated further in cancer patients, and the results have indicated that some have activity at safe doses. 

Polycyclic aromatic hydrocarbons (PAHs) represent a heterogeneous class of environmental contaminants formed by incomplete combustion or pyrolysis of organic matter. They comprise compounds with 2-6 fused benzene rings, most of which (4-6 ring compounds) are known human mutagens and carcinogens. 

The heterogeneous class of compounds marked by solubility in so-called lipid solvents (acetone, hydrocarbons, ether, etc.) and relative insolubility in water, has traditionally been called lipids (3). This historical classification, based upon isolation procedures from natural products, is obviously too broad for simple generalizations since it includes triglycerides, fatty acids, phospholipids, sterols, sterol esters, bile acids, waxes, hydrocarbons, fatty ethers and hydrocarbons. For the purposes of this chapter, we will consider lipids to be fatty acids and their derivatives. 

Basic nitrogen compounds in plants are classified as alkaloids. Several examples were given previously of this large and remarkably heterogeneous class of compounds, many of which have very complex structures (Section 23-2). It is difficult to give a coherent account of alkaloid chemistry in the limited space available to us here. 

Catalysts are usually subdivided into homogeneous and heterogeneous classes. Homogeneous catalysts are soluble in the reaction media. Heterogeneous catalysts make up the bulk of the catalyst market they are the solid catalysts that can be a support material, such as alumina, silica, or silica alumina, but more often some metal salt is added to a formed catalyst support. 

The discovery of the antidepressant effect of medications was coincidental to their use for other disorders. Initial work published in 1952 reported that iproniazid (originally used for the treatment of tuberculosis) could elevate mood. Although the use of iproniazid was discontinued due to toxicity, many other additional medications have been tested and approved for the treatment of depression. These include monoamine oxidase inhibitors, tricyclics, selective serotonin reuptake inhibitors, and a heterogeneous class of atypical drugs. 

Due to dynamic remodeling within different HDL subfractions and between HDL and other lipoproteins, HDL is a heterogeneous class of lipoproteins that can be generalized by a high density (>1.063 g/mL) and a small size (5- to 17-nm diameter). Differences are characterized by shape, density, size, charge, and antigenicity,... 

Structures of the most common phenolic extractives and related constituents are depicted in Fig. 5-8. They constitute a heterogeneous class of compounds, which may be divided into the following groups (1) Hydrolyz-... 

An understanding of the phase behavior of the SC lipids and of the structure/function relationship of these heterogeneous class of lipids is crucial to the understanding of the epidermal barrier function on a molecular level. But there has been relatively little work in this area, presumably because (a) the detailed lipid composition of SC was not known even as recently as 10 years ago (b) the methods used to isolate these nonphospholipids from... 

It is now clear that topoisomerases are a diverse and important group of enzymes. Although attention has until recendy been focused on their ability to interconvert DNA topoisomers, this does not necessarily constitute the primary biological function for all of them. For instance, the recombinases Int and resolvase can relax DNA but this probably represents a side reaction of their recombination activity. It is likely that other enzymes, already known for different activities, will also be shown to be topoisomerases. Conversely, enzymes currently established as topoisomerases may be found to have other catalytic activities. Thus topoisomerases represent a rather heterogeneous class of enzymes in terms of biological function, but nevertheless share the same basic chemistry of DNA breakage and reunion. 

Macrides F, Schoenfeld TA, Marchand JE, Clancy AN. 1985. Evidence for morphologically, neurochemically and functionally heterogeneous classes of mitral and tufted cells in the olfactory bulb. Chem Sens 2 175-202. 

HDL, the smallest of the lipoprotein particles (diameter 80-120 A, density range 1.063-1.210 g/ml, a-electrophoretic mobility. Fig. 1), constitute a heterogeneous class of lipoproteins that contain various subclasses of apolipoproteins (Fig. 2). 

Markie, S., Abels, S. (2013). Die Fachsprache der Chentie. Fin gemeinsames Anliegen von helerogenen Klasscai [The terminology of chemistry. A joint ctmcern of heterogenous classes]. Naturwissenschcften im Unterricht—Chemie, 24(135), 10-14. 

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