Pancreatic deoxyribonuclease

Deoxyribonuclease I [EC 3.1.21.1], also known as pancreatic DNase and thymonuclease, catalyzes the endonucleolytic cleavage of DNA, preferring dsDNA, to a 5 -phosphodinucleotide and 5 -phosphooligonucleotide end products. 

Deoxyribonuclease II [EC 3.1.22.1], also referred to as pancreatic DNase II, catalyzes the endonucleolytic hydrolysis of DNA (preferring double-stranded DNA) to produce 3 -phosphomononucleotide and 3 -phos-phooligonucleotide end products. 

The question of enzyme specificity for irradiated polynucleotides is taken up in more detail in the recent review of Johns.11 The specificities of four enzymes, spleen phosphodiesterase, snake venom phosphodiesterase, pancreatic ribonuclease, and pancreatic deoxyribonuclease are discussed. 

The reasons for selecting pancreatic DNase I as one of the two representative of mammalian DNases are to a large extent historical. Deoxyribonuclease I was the first enzyme to be recognized as specific for DNA (18-15), the first DNase to produce 5 -monoesterified products (16, 17), the first DNase to be crystallized (18), the first DNase to have a specific protein inhibitor (19-23), the first DNase shown to produce nicks on one strand in preference to scission of both strands (24, 25). A new first has been added recently (25a) DNase I was covalently coupled to porous glass, thus supplying an insoluble DNase. 

Amino Acid Composition of Pancreatic Deoxyribonuclease Peak A -b... 

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-... 

In this charter, wc will focus on the present insights into the structure-activity relationship and the clinical situation of this enzyme without attempting to iiuaiuic U relevant studies. For reviews on the biochemistry up to l9W, largely refer to the work of M. Laskowsfci [1], who was closely Involved in early studies on DNase I, and of S. Moore [9]. Moore shared with W. Stein Nobel Prize in Chemistry in 1972 fra their work on the chemical structures of pancreatic ribanudesae and deoxyribonuclease [ID]. 

Sk Moore and W. H. Stain. Chemical structure of pancreatic ribonudease and deoxyribonuclease- Science 160 458-464 (1673). 

J. Stuuiiujw, 8. Moure, anti "w. Stein Compsuon of multiple forms of bovine pancreatic deoxyribonuclease. J. BioL Chan. 245 5685-5690 (1970). 

T. Hugh. Hie preparation and characterization of an active derivative of bovine pancreatic deoxyribonuclease A formed by selective cleavage with a-chymotrypsin. J. BioL Chem. 24 1712-1718 (1973). 

T,-H. Liao. Reversible inactivation of pancreatic deoxyribonuclease A by sodium dodecyl sulfaic. Removal of the CQOH emninal residues from the denatured protein by csiboxypeptldase A. J. BioL Chem. 250 3831-3836 (1975). 

P. A. Price, S. Moore, and W- H. Stein. Alkylation of a histidine residue at the active site of bovine pancreatic deoxyribonuclease. J. Biot. Chem. 244 924-928... 

Felekkis K and Deltas C (2006) RNA interference A powerful laboratory tool and its therapeutic implications. Hippok 10(3) 112—115 Funakoshi A, Tsubota Y, Wakasugi H, Ibayashi H and Takagi Y (1977) Purification and properties of human pancreatic deoxyribonuclease I. J Biochem 82(6) 1771—1777... 

Bacterial nucleic acids were hydrolyzed using bovine pancreatic ribonuclease and deoxyribonuclease.37 Deoxyribonuclease treatment of disrupted bacterial suspensions has also been reported.38... 

Fig. 1. Chromatography of bovine pancreatic juice on DEAE-cellulose (anionic proteins) and Amberlite IRC-50 (cationic proteins) (1). RNAase, ribonuclease ChTg-a, chymotrypsinogen A Tg, trypsinogen ProCp-B and Cp-B, procarboxypeptidase B and carboxypeptidase B DNAase, deoxyribonuclease ProCp-A, procarboxypeptidase A.

Fig. 4. Chromatography of dog pancreatic juice on DEAE-cellulose (13, 14). The column is equilibrated with 0.005 M phosphate, pH 8.0 and eluted by a concentration gradient of phosphate indicated in the figure by a straight line. (1) Unfractionated cationic proteins (2) amylase (3) lipase (4) deoxyribonuclease (5) anionic chymotrypsinogen (6), (9), and (10) carboxypeptidase A and its precursor (7) and (8) carboxypeptidase B and its precursor. Ordinates on the left, optical density of the fractions at 280 m/ . Ordinates on the right, molarity of the phosphate. Abscissas, volume of eluate expressed in number of interstitial volumes of the column.

Keller and Cohen (36) also subjected to chromatography acidic extracts of cattle pancreatic microsomes and ribosomes. In microsomes they found the expected amounts of all enzymes which are known to be stable in acid, viz., chymotrypsinogen A, trypsinogen, deoxyribonuclease, and ribonuclease. The amounts of chymotrypsinogen B were abnormally low and ribonuclease B was perhaps not present. The results concerning ribosomes were made somewhat uncertain by the ability of these particles to incorporate proteins from the medium. Nevertheless, a series of characteristic enzymes could be isolated from what appears to be the very site of their biosynthesis. 

S. Moore and W.H. Stein. 1973. Chemical structures of pancreatic rihonuclease and deoxyribonuclease Science 180 458-464. (PubMed)... 

Fig. 10.1. Resolution of the low-molecular weight polynucleotide homologues by polyacrylamide gel electrophoresis a) polyriboadenylie acid after degradation with kidney exonuclease. Samples, run on a 12% gel correspond to incubation with the enzyme under various conditions and for dilTering times (Philippsen and Zachau 1972a) b) pancreatic deoxyribonuclease partial digest of poly (dAT), alternating double helical polymer, run in 22% cylindrical gel (Elson and Jovin 1969).

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