Pancreas deoxyribonuclease

The final pellet was diluted 1 20 with water, mixed, and immediately heated at 100° for 3 min. To 1 ml of this suspension was added 5 /u.1 of bovine pancreas deoxyribonuclease 1 (5 mg/ml Sigma). After a 30-min incubation at 37°, an equal volume of a solution of 2% weight/volume sodium dodecyl sulfate and 2% weight/volume /3-mercaptoethanol 2 mM EDTA-8 M urea was added. This mixture was immediately heated at 100° for 3 min. The polypeptides in the sample were separated by electrophoresis in SDS polyacrylamide gels. ... 

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). 

In the small intestine, ribonuclease and deoxyribonuclease I, which are secreted in the pancreatic juice, hydrolyze nucleic acids mainly to oligonucleotides. The oligonucleotides are further hydrolyzed by phosphodiesterases, also secreted by the pancreas, to yield 5 - and 3 -mononucleotides. Most of the mononucleotides are then hydrolyzed to nucleosides by various group-specific nucleotidases or by a variety of nonspecific phosphatases. The resulting nucleosides may be absorbed intact by the intestinal mucosa, or they may un-... 

Takeshita H, Mogi K, Yasuda T, Nakajima T, Nakashima Y, Mori S, Hoshino T and Kishi K (2000) Mammalian deoxyribonucleases I are classified into three types pancreas, parotid, and pancreas-parotid (mixed), based on differences in their tissue concentrations. Biochim Biophys Acta 269(2) 481 484... 

Deoxyribonuclease I Bovine pancreas DNA endonudease splits simple or double-stranded DNA spedfic for p bonds where pyrimidine nucleotides are in 3 position, produdng largely tetranudeotides... 

Deoxyribonuclease B bovine pancreas 4 Man, GIcNAc, Gal, Sialic acid 11... 

Ribonuclease from other mammalian sources may have several carbohydrate fragments in their structures. Thus, ribonuclease B from porcine pancreas contains at least three carbohydrate moieties, and these are attached9 at asparagine residues 21, 34, and 76. The carbohydrate moieties present at residues 21 and 76 are considerably more complex than that at residue 34, and their structures are under investigation in several laboratories. The carbohydrate portions of the isoenzymes of deoxyribonuclease are similar in structure to those from the ribonucleases.11 As ribonuclease and deoxyribonuclease originate in the same organ, it is possible that the same pathways and enzymes are utilized for the biosynthesis of the carbohydrate moieties of both enzymes. 

The pancreas also secretes a number of enzymes in tfcfii c/on , including a-amy-lase, lipase, deoxyribonuclease (DNase), and ribonuclease (RNase). DNase catalyzes the hydrolysis of DNA, resulting in the liberation of deoxyadenosine monophosphate (dAMP), dcoxythymidine monophosphate (dTMP), deoxyguanosine monophosphate (dGMP), and deoxycytosine monophosphate (dCMP). 

M. McCarty. Purification and properties of deoxyribonuclease isolated from beef pancreas. J. Gen Physiol. 29 123-139 (1946). 

Dietary uptake of purine and pyrimidine bases is minimal. The diet contains nucleic acids and the exocrine pancreas secretes deoxyribonuclease and ribonucle-ase, along with the proteolytic and lipolytic enzymes. This enables digested nucleic acids to be converted to nucleotides. The intestinal epithelial cells contain alkaline phosphatase activity, which will convert nucleotides to nucleosides. Other enzymes within the epithelial cells tend to metabolize the nucleosides to uric acid, or to salvage them for their own needs. Approximately 5% of ingested nucleotides will make it into the circulation, either as the free base or as a nucleoside. Because of the minimal dietary uptake of these important molecules, de novo synthesis of purines and pyrimidines is required. 

Deoxyribonuclease I, DNase I (EC 3.1.21.1) an enzyme (normally obtained from bovine pancreas and therefore also known as pancreatic deoxyribonuclease) which catalyses random endonucleolytic cleavage of intemucleotide bonds of double-stranded DNA, preferentially but not exclusively between adjacent purines and pyrimidines, producing S -phos-phodi- and -oligonucleotides. 

Deoxyribonuclease II, DNase H, pancreatic DNase II, acid DNase, calf thymus attid DNase, spleen acid DNase (EC 3.1.22.1) a monomeric enzyme (M, 31,(XK>) which catalyses the endonucleolytic cleavage of double stranded DNA to 3 -phosphomononu-cleotides and 3 -phosphooligonucleotides The earliest definitive studies were performed on the enzyme from hog spleen, which became known simply as hog-spleen enzyme . But the enzyme (or enzymes with extremely amilar properties) is widely distributed in animal cells, including, e.g. human pancreas, thymus, liver, gastric mucosa and cervix, as well as crab testis, snails and salmon testis. Although optimal activity occurs at pH 4-S, this optimum is not sharply defined, and considerable activity is retained even at neutral pH. 

Deoxyribonuclease DNase Dexoyribonucleate 5 -oligonucleotidohydrolase 3.1.4.5 Pancreas and small intestine DNA... 

Deoxyribonuclease I from pancreas breaks down high molecular weight deoxyribonucleic acids into oligonucleotides and a small amount of mononucleotides large parts of the polynucleotide structure are unaffected. Ribonucleic acids are unattacked. Deoxyribonucleases from snake venom are capable of breaking down deoxyribonucleic acids more completely than is the deoxyribonuclease I from pancreas. These enzymes have, however, not yet been adequately investigated. 

Deoxyribonucleases. Enzymes that hydrolyze DNA are called deoxyribonucleases (DNAases). In addition to specific enzymes foimd in various extracts, phosphodiesterases such as occur in snake venom hydrolyze DNA. Deoxyribonuclease has been isolated from pancreas.The crystalline enzyme is a protein with a molecular weight around 60,000 and an isoelectric point near pH 5. It requires divalent cations for activity. Like many previously discussed hydrolytic enzymes, it is reversibly denatured by heat. 

Deoxyribonucleases. The enzyme from the pancreas has been studied best and has been crystallized its molecular weight is 60,000 the pH optimum is around 6.0 to 7.0. It splits the 3 -phosphoester bond, freeing oligonucleotides. There remain also some nondialyzable, large fragments. 

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