Nucleic acids metabolism

Many enzymes involved in the pathways of intermediary metabolism are Mg2+ dependent, as are a great many of the enzymes involved in nucleic acid metabolism. Of the ten enzymes involved in the glycolytic pathway (see Chapter 5), five are Mg2+ dependent. 

Depending on diet and systemic (whole body) metabolism, which produces so-called fixed acids such as sulfate derived from sulfur-containing amino acids and phosphate, mainly from nucleic acid metabolism, there is a tendency for pH of body fluids to fall. 

The mechanism of inhibition of these protozoal infections by the most active drugs, puromycin and the aminonucleoside, is not known. Puromycin and nucleocidin both interfere with protein synthesis, but the aminonucleoside does not. It is known to be demethylated to 3 -amino-3-deoxyadenosine, which is phosphorylated and interferes with nucleic acid metabolism (see above). Whether puromycin must be converted to the aminonucleoside before it can inhibit protozoa has not been established. Some purine analogues known to interfere with nucleic acid metabolism, however, are less effective as antiprotozoal agents, even in vitro, perhaps because their effects are primarily on the de novo pathway which many, if not all, protozoa do not use [406]. 

Bone formation, energy metabolism, nucleic acid metabolism... 

Sixth, if the vast array of sites and site-important molecules is not enough, protein-protein interactions are part of most cellular processes including carbohydrate, lipid, protein, and nucleic acid metabolism, signal transduction, cellular architecture, and cell-cycle regulation. In fact, many of the major diseases are believed to involve a breakdown in such protein-protein interactions. These include some cancer, viral infections, and autoimmune disorders. 

Another evolving subdiscipline is interaction proteomics. Protein-protein interactions are a key element of almost all cellular processes. These interactions underlie the events of cell-cycle regulation, cellular architecture, intracellular signal transduction, nucleic acid metabolism, lipid metabolism, and carbohydrate metabolism. A rigorous... 

Studies of canavanine interaction with the tobacco hornworm and J-. miTior also revealed the marked ability of canavanine.to inhibit whole organism incorporation of [ Hjthymidine and uridine into trichloroacetic acid-precipitated materials. When canavanine is provided simultaneously with the appropriate radio-labeled precursor, ample evidence for curtailed nucleic acid metabolism emerges but protein synthesis is unaffected (Table I, exp. I). In experiment II, canavanine is allowed to assimilate... 

Silybum marianum (L.) Gaertn. Shui Fei Ji (fruit) Silybin, silymarin, silydiamin, silyckristin, dehydrosilybin, silybinomer.33 Maintain normal functioning of the liver, promote the regeneration of injured hepatic cells, increase glycogenesis and nucleic acid metabolism. 

Phosphatidylinositol Synthesis. The symptoms of inositol depletion include a decreased hyphal extension rate, increased branching and cell lysis. Other changes occur in protein, carbohydrate and nucleic acid metabolism, and reduced activity levels of membrane-bound wall biosynthetic enzymes.7... 

Nucleic acid metabolism is a feature that is common to all living things and few steps in the process in fungi are sufficiently different from those in other organisms to be used as an effective target for selective fungicides. Consequently, few compounds have been discovered that are not limited by their lack of specificity. In those fungicides known to inhibit nucleic acid biosynthesis the basis for the observed specificity is not understood. 

Several compounds may interfere with nucleic acid metabolism but commonly their effects are secondary to their primary mode of action, for example, the benzimidazoles. Compounds that inhibit nucleic acid biosynthesis directly are either phenylamides, pyrimidines or hydroxy-pyrimidines. Recently, the phenoxyquinolines were identified as exhibiting a novel mode of action in purine biosynthesis and are potentially useful fungicides. 

The dicarboximides inhibit spore germination and cause increased branching, swelling and lysis of germ tubes and hyphal tips. Effects on cell division have been reported but no major inhibition of nucleic acid metabolism, respiration, protein or lipid synthesis has been observed. 

G. Gustafson, Nucleic Acid Metabolism as a Target for Antifungals the mechanism of action of LY214352 , in Antifungal Agents. Discovery and Mode of Action , eds. G.K. Dixon, L.G. Copping and D.W. Hollomon, BIOS Scientific Publishers Ltd., Oxford, 1995, pp. 111-117. 

Auxins produce many changes in cells, including increased wall plasticity, enhanced respiratory rate and alterations in nucleic acid metabolism. Although the primary mode of action of auxins is not fully understood the development of the chemistry has progressed rapidly. Early discoveries identified and exploited the herbicide potential of super-optimal concentrations of auxin (Chapter 2, Herbicides) but their... 

Biotin is involved in many carboxylation and decarboxylation reactions in carbohydrate, fatty acid, protein, and nucleic acid metabolism. Milk is a fairly good source of this vitamin, generally providing about 3/xg/100 g. Pasteurization has a minimal effect on the biotin content of milk. 

Metallothioneins probably participate in other cellular functions, for example in nucleic acid metabolism.1168... 

Isoniazid (INH, Laniazid, Nydrazid, other names) is one of the primary drugs used to treat tuberculosis.24,61 Although the exact mechanism of action is unknown, this drug appears to interfere with several enzymatic pathways involving protein, lipid, carbohydrate, and nucleic acid metabolism in susceptible bacteria. Adverse reactions to isoniazid are common, and patients may develop disorders such as hepatitis and peripheral neuropathies. 

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