Functional diversity

Therapeutic enzymes have a broad variety of specific uses, ie, as oncolytics, thrombolytics, or replacements for inherited deficiencies. Additionally, there is a growing group of miscellaneous enzymes of diverse function. 

In retrospect it is easy to see that such structural irregularity is actually required for proteins to fulfill their diverse functions. Information storage and transfer from DNA is essentially linear, and DNA molecules of very different information content can therefore have essentially the same gross structure. In contrast, proteins must recognize many thousands of different molecules in the cell by detailed three-dimensional interactions, which... 

The number of possible ways to form antiparallel p structures is very large. The number of topologies actually observed is small, and most p structures fall into these three major groups of barrel structures. The last two groups—the Greek key and jelly roll barrels—include proteins of quite diverse function, where functional variability is achieved by differences in the loop regions that connect the p strands that build up the common core region. 

Much work is still appearing on the [l,2,4]triazino[5,6-b]indole ring system since its first synthesis, due to its varied biological properties. Moreover, it has been used as a carrier for diverse functional groups suitable for the development of several chemotherapeutic agents. In addi-... 

Epoxides are often encountered in nature, both as intermediates in key biosynthetic pathways and as secondary metabolites. The selective epoxidation of squa-lene, resulting in 2,3-squalene oxide, for example, is the prelude to the remarkable olefin oligomerization cascade that creates the steroid nucleus [7]. Tetrahydrodiols, the ultimate products of metabolism of polycyclic aromatic hydrocarbons, bind to the nucleic acids of mammalian cells and are implicated in carcinogenesis [8], In organic synthesis, epoxides are invaluable building blocks for introduction of diverse functionality into the hydrocarbon backbone in a 1,2-fashion. It is therefore not surprising that chemistry of epoxides has received much attention [9]. 

Terpenoid substances are of broad distribution and diverse function in insects. One set, elaborated by the mandibular glands of Acanthomyops claviger, acts both as a defensive secretion and as an alarm releaser. When fed Cu-labeled acetate or mevalonate, laboratory colonies of these ants produce radioactive citronellal and citral, providing unambiguous evidence for de novo synthesis of these terpenes by the ant. The incorporations of these precursors implicate the mevalonic acid pathway as the likely biosynthetic route. 

Glycoproteins occur in most organisms, from bacteria to humans. Many vimses also contain glycoproteins, some of which have been much investigated, in part because they are very suitable for biosynthetic studies. Numerous proteins with diverse functions are glycoproteins (Table 47-1) their carbohydrate content ranges from 1% to over 85% by weight. 

Glycoproteins are widely distributed proteins— with diverse functions—that contain one or more covalently linked carbohydrate chains. 

The endothelium has many diverse functions that enable it to participate in in-flammatoiy reactions (H27). These include modulation of vascular tone, and hence control of local blood flow changes in structure that allow leakage of fluids and plasma proteins into extravascular tissues local accumulation and subsequent extravasation into tissues of leukocytes and synthesis of surface molecules and soluble factors involved in leukocyte activation (B43). The endothelial cells themselves can modulate vascular tone by the release of vasoactive substances such as prostacyclin, nitric oxide (NO), ET. Endothelium-derived vasoactive substances... 

Martin C, Zhang Y (2005) The diverse functions of histone lysine methylation. Nat Rev Mol Cell Biol 6 838-849... 

Nitro compounds are versatile precursors for diverse functionalities. Their conversion into carbonyl compounds by the Nef reaction and into amines by reduction are the most widely used processes in organic synthesis using nitro compounds. In addition, dehydration of primary nitro compounds leads to nitrile oxides, a class of reactive 1,3-dipolar reagents. Nitro compounds are also good precursors for various nitrogen derivatives such as nitriles, oximes, hydroxylamines, and imines. These transformations of nitro compounds are well established and are used routinely in organic synthesis. 

Molecular mechanics is a useful and reliable computational method for structure, energy, and other molecular properties. The mathematical basis for molecular models in MM3 has been described, along with the limitations of the method. One of the major difficulties associated with molecular mechanics, in general, and MM3 in particular is the lack of accurately parameterized diverse functional groups. This lack of diverse functional groups has severely limited the use of MM3 in pharmaceutical applications. 

These are just some examples of the diverse functions of RGS proteins in mammalian cells. Given the number and diversity of RGS proteins, and their region-specific expression in brain, there is considerable interest in... 

Steroid hormones regulate a very extensive assembly of functions in numerous corporal tissues. Estrogens, the steroid hormones to which the majority of this chapter is dedicated, regulate from basic functions related to reproduction, the development of the skeleton, the maintenance of arterial tension, or diverse nervous functions. The molecular studies on the mechanism of action of estrogens have set the foundations that will permit us to understand how they carry out such diverse functions in such dissimilar tissues as well as how some substances that act through the estrogen signaling pathway can exercise opposite functions in different tissues. In this respect, there are five facts of particular importance that constitute the central nucleus of this revision ... 

Much knowledge has been gathered about signaling mechanisms of G-protein to date, but many questions remained unanswered and new areas of investigation have opened. PAL is a particularly valuable tool for studying intracellular protein-protein interactions and the diverse function of second messengers. 

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