Pancreas ribonuclease

Protein adsorption on solid surfaces is discussed from a colloid chemical and thermodynamic point of view. Information is mainly obtained from adsorption isotherms, (proton)titrations, electrokinetics and calorimetry. The adsorption behavior of human plasma albumin and bovine pancreas ribonuclease at various surfaces is studied. The differences in behavior between the two proteins are related to differences in the structural properties. Furthermore, the essential role of the low molecular weight electrolytes in the overall protein adsorption process is stressed. 

Figure 2. Plateau values for the adsorption of bovine pancreas ribonuclease on polystyrene latex (o), polyoxymethylene ( ) and hematite (x). Conditions as in Figure 1.

Figure A. Charge transfer (expressed per unit area of the sorbent surface) between the solution and adsorbed layers of human plasma albumin (HPA) and bovine pancreas ribonuclease (RNase) on various sorbents. Plateau adsorption.

IV) Nucleases from pancreas Ribonuclease 13700 3 -Phosphate ester bonds 7.3... 

Figure 4.8 Cation-exchange liquid chromatography of basic proteins. Column, Asahipak ES502C eluent, 20 min linear gradient of sodium chloride from 0 to 500 mM in 50 mM sodium phosphate buffer pH 7.0 flow rate, 1 ml min-1 temperature, 30 °C detection, UV 280 nm. Peaks 1, myoglobin from horse skeletal muscle (Mr 17 500, pi 6.8-7.3) 2, ribonuclease from bovine pancreas (Mr 13 700, pi 9.5-9.6) 3, a-chymotrypsinogen A from bovine pancreas (Mr 257 000, pi 9.5) and 4, lysozyme from egg white (Mr 14 300, pi 11.0-11.4). (Reproduced by permission from Asahikasei data)...

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). 

Ribonuclease A, Bovine pancreas. Horse heart. AOT/isooctane Solubilization [72]... 

Ribonuclease, another small globular protein (Mt 13,700), is an enzyme secreted by the pancreas into the small intestine, where it catalyzes the hydrolysis of certain bonds in the ribonucleic acids present in ingested... 

In view of the high stability of the enzyme most samples have been prepared by the procedure described by Kunitz (16) and modified by McDonald (17) to remove all traces of proteolytic activity. During this procedure the minced bovine pancreas is exposed to 0.25 N sulfuric acid, ammonium sulfate precipitation, 10 min at 95°-100° and pH 3, and, finally, reprecipitation. The product can be crystallized it was also shown later to contain a number of components all with ribonuclease activity. A practical summary of all details is given by Kunitz and McDonald (18). 

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-... 

W3. Warshaw, A. L., and Fournier, F., Release of ribonuclease from anoxic pancreas. Surgery 95, 537-540 (1984). 

MATERIALS. Ribonuclease A (RNase A) (bovine pancreas), cytochrome C (Cyt. C) (horse heart), lysozyme (chicken egg white), myoglobin (sperm whale), P-lactoglobulin A... 

Ribonuclease I Bovine pancreas RNA endonuclease splits d bonds where pyrimidine nucleotides are in 3 position... 

Many of the nucleic acid hydrolases occur in isoenzymic forms in mammalian tissues. Some of these isoenzymes are glycoenzymes, and information on these is contained in Table I. Ribonuclease B has been studied in the greatest detail. Following the initial observation that the ribonuclease from bovine pancreas occurs in isoenzymic forms,45 it was found that one form (ribonuclease B) contains an appreciable... 

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. 

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