Deoxyribonucleases

Deoxyribonuclease (DNAase), an enzyme that degrades deoxyribonucleic acid, has been used in patients with chronic bronchitis, and found to produce favorable responses presumably by degrading the DNA, contributed by cell nuclei, to inflammatory mucus (213). Lysozyme [9001 -63-2] hydrolyzes the mucopeptides of bacterial cell walls. Accordingly, it has been used as an antibacterial agent, usually in combination with standard antibiotics. Topical apphcations are also useful in the debridement of serious bums, cellulitis, and dermal ulceration. 

Fractionated ammonium sulfate precipitaion of a-chymotrypsinogen (further fractions contain deoxyribonuclease, chymotrypsinogen B, ribonuclease, trypsinogen). 

CN deoxyribonuclease (human clone 18-1 protein moiety reduced)... 

Amylases, peptidases and deoxyribonuclease mobilize many nutrients that are released from lysed cells. They also deerease the viseosity of fluids present at the lesion by depolymerization of their biopolymer substrates. 

Restriction endonuclease A deoxyribonuclease which cuts DNA at specific sequences which exhibit twofold symmetry about a point. Name derives from the fact that their presence in a bacterial cell prevents (restricts) the growth of many infecting bacteriophages. 

A second errzyme, streptodornase, preserrt in streptococcal cirltiue filtrates, was observed to hqnefy pus. Streptodornase is a deoxyribonuclease which breaks down deoxyribonucleoprotein and DNA, both constituents of pits, with a consequent reduction in viscosity. Streptokinase and streptodornase together have been used to facilitate... 

Maruyama, T., Sonokawa, S. and Matsushitaa, H. Goto, M. (2007) Inhibitory effects of gold(III) ions on ribonuclease and deoxyribonuclease. Journal of Inorganic Biochemistry, 101, 180-186. 

Okada, S. and Gehrmann, G. (1957). Inactivation of deoxyribonuclease I by X-rays. Biochim. Biophys. Acta 25, 179-182. 

Cacia, J., Quan, C. P., Vasser, M., Sliwkowski, M. B., and Frenz, J., Protein sorting by high-performance liquid chromatography I. Biomimetic interaction chromatography of recombinant human deoxyribonuclease I on polyionic stationary phases, /. Chromatogr., 634, 229, 1993. 

A major advantage of DNA as a carrier is that no chemical synthesis or manipulations are needed to obtain DNA-drug complex. The efficacy of the DNA-drug complex depends on stability in the bloodstream, endocytic behavior of normal and tumor cells, presence of extra-cellular deoxyribonuclease activity in the tumor tissues, and capillary barriers that separate normal and tumor cells from the bloodstream. 

The histone core protects the DNA bound to the nucleosome from digestion by pan-creatic deoxyribonuclease (DNase) I or micrococcal nuclease. Nucleases, however, will cleave the linker DNA that connects the nucleosome subunits to one another. 

Enzyme activity has been sought in seawater Strickland and Solorzano [288] looked for photomono esterase activity, while Maeda and Taga [289] used a flu-orometric method for assaying deoxyribonuclease activity in both seawater and sediment samples. 

Humidification of inspired air may promote the hydration (liquefaction) of tenacious secretions, allowing for more effective sputum production. The use of mucolytic aerosols (e.g., N-acetylcysteine deoxyribonuclease) is of questionable therapeutic value. Mucolytics may have the greatest benefit... 

Daoust R. Localization of deoxyribonuclease in tissue sections. A new approach to the histochemistry of enzymes. Exp Cell Res 1957 12 203-211. 

List of Abbreviations PCR, polymerase chain reaction RT-PCR, reverse transcription polymerase chain reaction DNA, deoxyribonucleic acid RNA, ribonucleic acid RNase, ribonuclease mRNA, messenger RNA GABAa, y-aminobutyric acid type A cRNA, copy RNA dNTPs, deoxy nucleoside triphosphates MMLV, Mouse Moloney murine leukemia vims RT, reverse transcriptase bp, base pair Tm, melting temperature DEPC, diethylpyrocarbonate OD, optical density mL, milliliter SA-PMPs, streptavidin paramagnetic particles dT, deoxy thymidine DTT, dithiothreitol DNase, deoxyribonuclease RNasin, ribonuclease inhibitor UV, ultraviolet TBE, Tris-borate, 1 mM EDTA EDTA, ethylenediaminetetraacetic acid Buffer RET, guanidium thiocyanate lysis buffer PBS, phosphate buffered saline NT2, Ntera 2 neural progenitor cells... 

List of Abbreviations BCIP, 5-bromo-4-chloro-3-indolyl phosphate, toluidine salt CCD, charged-coupled device CNS, central nervous system cDNA, copy or complimentary RNA cRNA, copy or complimentary RNA DNase, deoxyribonuclease FITC, fluorescein isothiocyanate mRNA, messenger RNA NBT, nitro blue tetrazolium choride PCR, polymerase chain reaction RNase, ribonclease... 

Patients suffering from cystic fibrosis often use various aerosolized drugs. To reduce the viscosity of the mucus in the airways, recombinant human deoxyribonuclease is used. This enzyme is the first recombinant protein that has been developed for specific delivery to the lungs via the airways. It has a local action on the mucus in the airways and its absorption is minimal. Another drug that decreases the viscosity of the mucus is acetylcysteine. Aerosolized antibiotics are a further group of therapeutics that is widely used by cystic fibrosis patients. Solutions of antibiotics like tobramycin or colistin are used in nebulizers to prevent exacerbation of the disease. Pentamidine has been used for the prophylaxis of Pneumocystis pneumonia in patients infected with HIV virus, while chronic rejection of lung transplants provided a reason to develop an aerosol formulation of cyclosporine A. 

Small amounts of surfactants may be used to prevent aggregation of proteins and may enhance the refolding process when the dried protein dissolves. Buffers may also help to prevent aggregation of the dissolved drug. Similarly, polymers may be used as aggregation inhibitors or to form matrices. Chan et al. [86] prepared crystalline powders of recombinant human deoxyribonuclease with high fractions of sodium chloride. These powders were formulated as adhesive mixtures on lactose and mannitol and showed improved aerosolization behaviour compared to the pure protein. 

In addition to the enzymes that catalyse the formation of nucleotides and polynucleotides, a large number of catabolic systems exist which operate at all levels of the internucleotide pathways. The ribonucleases and deoxyribonucleases that degrade polynucleotides are probably not significantly involved in purine analogue metabolism, but the enzymes which dephosphorylate nucleoside 5 -monophosphates are known to attack analogue nucleotides and may be of some importance to their in vivo activity. Phosphatases of low specificity are abundant in many tissues [38], particularly the intestine [29]. Purified mammalian 5-nucleotidases hydrolyse only the nucleoside 5 monophosphates [28] and... 

These three compounds exert many similar effects in nucleotide metabolism of chicks and rats [167]. They cause an increase of the liver RNA content and of the nucleotide content of the acid-soluble fraction in chicks [168], as well as an increase in rate of turnover of these polynucleotide structures [169,170]. Further experiments in chicks indicate that orotic acid, vitamin B12 and methionine exert a certain action on the activity of liver deoxyribonuclease, but have no effect on ribonuclease. Their effect is believed to be on the biosynthetic process rather than on catabolism [171]. Both orotic acid and vitamin Bu increase the levels of dihydrofolate reductase (EC 1.5.1.4), formyltetrahydrofolate synthetase and serine hydroxymethyl transferase in the chicken liver when added in diet. It is believed that orotic acid may act directly on the enzymes involved in the synthesis and interconversion of one-carbon folic acid derivatives [172]. The protein incorporation of serine, but not of leucine or methionine, is increased in the presence of either orotic acid or vitamin B12 [173]. In addition, these two compounds also exert a similar effect on the increased formate incorporation into the RNA of liver cell fractions in chicks [174—176]. It is therefore postulated that there may be a common role of orotic acid and vitamin Bj2 at the level of the transcription process in m-RNA biosynthesis [174—176]. 

Nucleic acids are broken down into their components by nucleases from the pancreas and small intestine (ribonucleases and deoxyribonucleases). Further breakdown yields the nucleobases (purine and pyrimidine derivatives), pentoses (ribose and deoxyribose). 

Several hydrolases—particularly ribo-nuclease (RNAse) and deoxyribonuclease (DNAse)—break down the nucleic acids contained in food. 

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