Ribonuclease and

Synthesis of oxorhenium(V) and oxotechnetium(V) complexes as inhibitors of ribonucleases and for generation of catalytic antibodies 97SL537. 

For many solubilized enzymes the greatest catalytic activity and/or changes in conformation are found at R < 12, namely, when the competition for the water in the system between surfactant head groups and biopolymers is strong. This emphasizes the importance of the hydration water surrounding the biopolymer on its reactivity and conformation [13], It has been reported that enzymes incorporated in the aqueous polar core of the reversed micelles are protected against denaturation and that the distribution of some proteins, such as chymotrypsine, ribonuclease, and cytochrome c, is well described by a Poisson distribution. The protein state and reactivity were found markedly different from those observed in bulk aqueous solution [178,179],... 

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. 

Levitt, M. Sander, C. Stem, P.S., Protein normal-mode dynamics - trypsin-inhibitor, crambin, ribonuclease and lysozyme, 7. Mol. Biol. 1985,181, 423 47... 

Many extracellular proteins like immunoglobulins, protein hormones, serum albumin, pepsin, trypsin, ribonuclease, and others contain one or more indigenous disulfide bonds. For functional and structural studies of proteins, it is often necessary to cleave these disulfide bridges. Disulfide bonds in proteins are commonly reduced with small, soluble mercaptans, such as DTT, TCEP, 2-mercaptoethanol, thioglycolic acid, cysteine, etc. High concentrations of mercaptans (molar excess of 20- to 1,000-fold) are usually required to drive the reduction to completion. 

The most convincing evidence in favor of a uniform 3,5-diester linkage between nucleotides has been obtained by the action of various enzymes on synthetic diesters of known constitution.218 217 Ribonuclease and spleen extracts were found to act only on nucleoside 3-(benzyl hydrogen phosphates), but not on other isomers, to give nucleoside cyclic phosphates which are broken down further to give nucleoside 3-phosphates. It is concluded, by analogy, that polynucleotides, which are substrates for these enzymes, also possess ester groupings at the 3-positions, rather than at the... 

Vanadium is beneficial and possibly essential for humans. It is certainly essential for a number of organisms. Vanadate (oxidation state V) and its derivatives are phosphate analogues, showing both ground state and transition state analogy (both structural and electronic) with phosphorus compounds. The analogy of five-coordinate vanadium compounds with the transition state of phosphate ester hydrolysis is well documented, and explains why so many vanadium compounds are potent inhibitors of phosphatases, ribonucleases and ATPases. 

Privalov, P.L., N.N. Khechinashvili, and B.P. Atanasov. 1971. Thermodynamic analysis of thermal transitions in globular proteins. I. Calorimetric study of chy-motrypsinogen, ribonuclease and myoglobin. Biopolymers 10 1865-1890. 

Jokichi Takamine (1854-1922) went to the University of Glasgow, and then, to the United States to investigate the phosphatic manure, and he established the first company of phosphatic manure in Japan. He produced Takadiastase, a digestive agent containing various digestive enzymes, ribonuclease and cellulase. Amylase was extracted from Takadiastase. In a narrow sense, Takadiastase is one of the carboxyoroteases. He discovered in 1900. 

Goldberger, R., and C. B. Anftnsen Reversible masking of amino-groups in ribonuclease and its possible usefulness in the sjmthcsis of the protein. Biochemistry /. 401—405 (1962). 

Among the specific enzymes whose activity has been reported to be decreased after in vitro ozone exposure are papain, glyceraldehyde-3-phosphate dehydrogenase, lysozyme, ribonuclease, and acetylcholinesterase. The latter enzyme appears to be particulady susceptible to free-radical and oxidative states. A loss in acetylcholinesterase activity has been reported in the red cells of humans and mice that inhaled ozone. However, there are only minimal amounts of this enzyme in lupg tissue, and, although it has been suggested that acetylcholinesterase is important in bronchial tract ciliary activity, there is no direct evidence to support this conjecture. 

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... 

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). 

A potent enzyme inhibitor (abbreviated DEP) that acts by ethoxyformylation of proteins, usually at histidine residues. DEP is an irreversible inhibitor of ribonuclease, and rinsing glassware with a 0.1% (weight/volume) DEP solution is recommended to render glassware nuclease-free. Aqueous solutions must be freshly prepared for maximal effectiveness, because DEP will hydrolyze in 6-12 hours at neutral pH. 

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. 

Veronese, F.M., Largajolli, R., Boccu, E., Benassi, C.A., and Schiavon, O. (1985). Surface modification of proteins activation of monomethoxy-polyethylene glycols by phe-nylchloroformates and modification of ribonuclease and superoxide dismutase. Alied Biochem. Biotechnol., 11, 141-152. 

SO is capable of oxidizing reduced ribonuclease and restoring enzymic activity, suggesting that its physiological role may be the non-random formation of protein disulphide bonds, e.g. during protein biosynthesis. 

Urea is used to denature ribonuclease, and mercaptoethanol (HOCH2CH2SH) to reduce and thus cleave the disulfide bonds to yield eight Cys residues. Renaturation involves reestablishment of the correct disulfide cross-links. 

The constant of proportionality, D, is the diffusion coefficient, and the negative sign is necessary because the net flux is from the region of high concentration to the region of low concentration. Table 23-1 shows that diffusion in liquids is 104 times slower than diffusion in gases. Macromole-cules such as ribonuclease and albumin diffuse 10 to 100 times slower than small molecules. 

Sequencing RNA. The first known RNA sequence, that of an alanine tRNA, was determined by Holley and associates in 1965. The RNA was subjected to partial hydrolysis with pancreatic ribonuclease and ribonuclease Tj (Fig. 5-43). Tire small oligonucleotide fragments were separated by ion exchange chromatography under denaturing conditions (7 M urea) and were then characterized individually.645 Tire availability... 

Although inversion was not observed with the E. colt alkaline phosphatase, it has been observed for ribonucleases and many other hydrolytic enzymes and for most kinases transferring phospho groups from ATP. The difference lies in the existence of a phospho-enzyme intermediate in the action of alkaline phosphatase (see Eq. 12-38). Each of the two phosphotransferase steps in the phosphatase action apparently occurs with inversion. The simplest interpretation of all the experimental results is that phosphotransferases usually act by in-line -like mechanisms which may involve metaphosphate-ion-like transition states that are constrained to react with an incoming nucleophile to give inversion. An adjacent attack with pseudorotation would probably retain the original configuration and is therefore excluded. 

The enzyme obtained by this purification procedure 11), when tested for contaminants under very stringent conditions, was found to be completely free from phosphatase, DNase, ribonuclease, and adenosine deaminase activities. 

In interesting recent studies, Poliak and co-workers (67, 68) have observed glucose-6-P phosphohydrolase, acid inorganic pyrophosphatase, and PPi-glucose phosphotransferase activities to be considerably higher in lipid-poor reticulosomes than in microsomal preparations. They hypothesized that reticulosomes, which they prepared by treatment of microsomal preparations from rat and chick livers with ribonuclease and deoxycholate (68), may be the precursors of endoplasmic reticulum, and... 

This review does not discuss any of the extensive work on the effects of ionizing radiation or on the immunochemistry of ribonuclease. The comparative aspects of the various ribonucleases and their possible biological roles are well covered by Barnard (10), and a number of the related enzymes are discussed in other chapters in this volume. Egami and Nakamura (11) have reviewed the microbial ribonucleases in a separate book. 

Naturally Occurring Forms of Pancreatic Ribonuclease and Well-Defined Main Chain Cleavage Products... 

A large number of reagents have been tried on ribonuclease, and the enzyme serves frequently as a test protein. Some of the reagents not described above are listed in Table X (214-222). In general the products of the reactions either have not been well characterized or the sites of modification in the sequence have not been established. 

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