Deoxyribonucleic acid defined

Closed circuit voltage, 3 410 Closed-circular DNA, 27 611. See also Deoxyribonucleic acid (DNA) Closed-closed tubular reactors, 25 288 Closed-loop bioremediation defined, 3 759t... 

Ribonucleases (RNases) may be defined as phosphodiesterases that attack the internucleotide bonds in ribonucleic acid (RNA) and its products but not those in deoxyribonucleic acid (DNA) or simple phos-phodiesters such as bis-p-nitrophenyl phosphate. 

Because of the presence of the cyclic four-membered amide connected to the multicyclic ring systems, an effort to define their mechanism of action would be highly important. Despite a number of synthetic efforts, a relatively small amount of research had been focused on the use of compounds related to PAHs as anticancer agents. Bair et al. [152, 153] reported a close correlation between antitumor activity and the shape of the polyaromatic system. However, his group did not make a definitive correlation between the ability of these compounds to bind to deoxyribonucleic acid (DNA) and their cytotoxic activity. Bair s group developed... 

Walsh (2003) defined biopharmaceuticals as therapeutic protein or nucleic acid preparations made by techniques involving recombinant deoxyribonucleic acid (DNA) technology. Therapeutic proteins include blood clotting factors and plasminogen activators, hemopoietic factors, hormones, interferons and interleukins, and monoclonal antibodies (LeVine, 2006). Over time, the term biopharmaceutical has broadened, and, in addition to proteins and nucleic acids, now includes bacteriophages, viral and bacterial vaccines, vectors for gene therapy, and cells for cell therapy (Primrose and Twyman, 2004). Attention here focuses on proteins, since the majority of approved biopharmaceuticals are proteins. 

As much of the terminology used in molecular biology may be unfamiliar to some readers, it is appropriate to define some of the vocabulary and this is given in an appendix to this chapter. There are two types of nucleic acids, the ribonucleic acids (RNA) and the deoxyribonucleic acids (DNA). Genetic information is carried in the linear sequence of nucleotides in DNA. Each molecule of DNA contains two complementary strands of deoxyribonucleotides which contain the purine bases, adenine and guanine and the pyrimidines, cytosine and thymine. RNA is single-stranded, being composed of a linear sequence of ribonucleotides the bases are the same as in DNA with the exception that thymine is replaced by the closely related base uracil. DNA replication occurs by the polymerisation of a new complementary strand on to each of the old strands. 

The mode of biological activity of mustard is less well defined than that of the nerve agents. The initial event is felt to be a reaction of mustard and deoxyribonucleic acid (DNA) with subsequent damage to the DNA. A series of intracellular events then occur, leading to cellular damage accompanied by inflammation and cellular death. Cellular damage begins within 1 to 2 minutes of contact of mustard to skin or mucous membranes.6... 

Deoxyribonucleic acids possess between several thousand and several thousand million base pairs per molecule (Table 29-3). The molar masses vary correspondingly from several million upwards. The extremely high complexity is characteristic for DNAs. Here, the complexity is defined as the number of base pairs that are in nonrepeating sequences. The complexity of simple natural DNAs is already about 10 -10. ... 

The directed synthesis of deoxyribonucleic acid (DNA) and its manipulation for genetic engineering would be impossible without enzyme catalysis. There is a range of restriction enzymes which can break DNA strands at specific points defined by the local base sequence, as well as ligases which can rejoin the broken ends where new base sequences are inserted, and they are essential catalysts. They complement the chemical synthesis of the oligonucleotides (small segments of DNA) which are inserted. A discussion of the technique is outside the scope of this chapter, largely because the... 

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