Ribonuclease, ribonucleic acid

Oligonucleotides have also been separated by ion-exchange chromatography of yeast ribonucleic acid treated either with acid216 or with ribonuclease.209 Alkaline hydrolysis of the fission products obtained with the latter gives rise to pyrimidine nucleoside 3-phosphates and mixtures of purine nucleoside 2- and 3-phosphates. Bone phosphomonoesterase196 followed by alkaline hydrolysis gives pyrimidine nucleosides and purine... 

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... 

Chirgwin JM, Pryzbyla AE, MacDonald RJ, Rutter WJ. 1979. Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease. Biochemistry 18 5294-5299. 

List of Abbreviations cDNA, complementary DNA ddH20, double-distilled H2O dNTP, deoxyribonu-cleotide triphosphate EDTA, ethylenediaminetetraacetic acid MgCl2, magnesium chloride mRNA, messenger ribonucleic acid NaOH, sodium hydroxide PCR, polymerase chain reaction qRT PCR, quantitative reverse transcriptase polymerase chain reaction RNase, ribonuclease RT PCR, reverse transcriptase polymerase chain reaction UTR, untranslated region... 

The following reviews describe the molecular and physical properties of this broad class of enzymes that catalyze the endohydrolysis of deoxyribonucleic acids and ribonucleic acids. The class includes deoxyribonuclease II [EC 3.1.22.1], Aspergillus deoxyribonuclease Ki [EC 3.1.22.2], deoxyribonuclease V [EC 3.1.22.3], crossover junction endoribonuclease [EC 3.1.22.4], and deoxyribonuclease X [EC 3.1.22.5]. See also Deoxyribonucleases Restriction Enzymes Ribonucleases... 

The pH-rate profile for the action of the enzyme shows a typical pH maximum, with sharply lower rates at either higher or lower pH than the optimum these facts suggest that both an acidic and a basic group are required for activity (Herries, 1960). The two essential histidine residues could serve as these groups if, in the active site, one were protonated and the other present in its basic form. The simultaneous acid-base catalysis would parallel that of the model system (discussed below) of Swain and J. F. Brown. The essential lysine, which binds phosphate, presumably serves to bind a phosphate residue of the ribonucleic acid. These facts led Mathias and coworkers to propose the mechanism for the action of ribonuclease that is shown in (13) (Findlay et al., 1961). 

Fig. 1. The two-step hydrolysis of ribonucleic acid as catalyzed by bovine pancreatic ribonuclease A.

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... 

Ribonuclease is an enzyme with 124 amino acids. Its function is to cleave ribonucleic acid (RNA) into small fragments. A solution containing pure protein, with no other ions present except H+ and OH- derived from the protein and water, is said to be isoionic. From this point near pH 9.6 in the graph, the protein can be titrated with acid or base. Of the 124 amino acids, 16 can be protonated by acid and 20 can lose protons to added base. From the shape of the titration curve, it is possible to deduce the approximate pATa for each titratable group.1-2 This information provides insight into the environment of that amino acid in the protein. In ribonuclease, three tyrosine residues have "normal values of pATa(=10) (Table 10-1) and three others have pA a >12. The interpretation is that three tyrosine groups are accessible to OH, and three are buried inside the protein where they cannot be easily titrated. The solid line in the illustration is calculated from pA"a values for all titratable groups. 

A series of carboxyl derivatized polyglucoses were studied as inhibitors of ribonuclease activity, in an attempt to relate charge density to inhibitory activity.202 In comparison with other factors, it was concluded that coulombic forces probably play a major role in complex-formation between enzyme and substrate, and between enzyme and inhibitor. However, other specific, nonelectrostatic forces were shown to participate in the binding of bovine pancreatic ribonuclease to ribonucleic acid.204... 

RIBONUCLEASE. An enzyme that causes splitting of ribonucleic acid, Pancreatic ribonuclease for example, cleaves only phosphodiester bonds... 

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. 

Studies on microbial RNases began in 1924 when Noguchi found ribonucleic acid degrading enzymes in Takadiastase (134). Since then extensive studies have been carried out on RNA degrading enzymes. It is rather surprising that guanyloribonuclease so widely distributed in microorganisms was found only in 1957. This is because earlier studies did not consider base specificity. Even quite recently studies on nucleases or ribonucleases do not consider base specificity or do not separate nuclease mixtures from each other thus, information available on microbial RNases is still scant. 

The ribonucleases are a class of enzymes catalyzing the hydrolytic cleavage of ribonucleic acids. Although such activity can be demonstrated in almost all tissues both plant and animal, relatively few of... 

Ribonuclease A is a rather small but critically important enzyme that catalyzes the hydrolysis of ribonucleic acid and, therefore, is crucial for cell function. It has been the subject of intense study for many years [48], As depicted in Scheme 11.1,... 

The nucleases are enzymes that hydrolyse nucleic acids, either deoxyribonucleases (DNases) that have DNA as the substrate or ribonucleases (RNases) that have ribonucleic acids as the substrate. The DNases hydrolyse the phosphodiester linkages between the deoxyribose molecules of DNA, and similarly, the RNases attack the equivalent bonds in RNA. There are many nucleases found in mammalian tissues, and as in the case of the peptidases, they can be divided into the categories endo and exo based on whether they attack bonds in the interior of the nucleic acid molecule or remove nucleosides from the end termini of the chains. They... 

Ribonuclease, the enzyme that hydrolyzes ribonucleic acids (Chap. 7), contains four disulfide bonds that help to stabilize its conformation. In the presence of 6 M guanidine hydrochloride, to weaken hydrogen bonds and hydrophobic interactions, and 1 mM mercaptoethanol, to reduce the disulfide bonds, all enzymatic activity is lost, and there is no sign of residual secondary structure. On removing the guanidine hydrochloride by dialysis or gel filtration, enzymatic activity is restored, the native conformation is regained, and correct disulfide bonds are reformed. 

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