Ribonuclease activity

Drought also has a profound effect on protein synthesis. In many plant tissues, a reduced water potential causes a reduction of total protein synthesis and a rapid dissociation of polyribosomes. The latter has been shown not to be the consequence of increase in ribonuclease activity (Hsiao, 1973 Dhindsa Bewley, 1976). For a specific protein, Jacobsen, Hanson Chandler (1986) have shown in barley leaves that water stress enhances the synthesis of one of the a-amylase isozymes. Using a cDNA probe they found that water-stressed leaves contained much more a-amylase mRNA than unstressed plants. 

Christenson, G.M. and Olson, D.L. (1981) Effect of water pollutants and other chemicals upon ribonuclease activity... 

Komiyama at al. have prepared two oligonuclear Zn(II) complexes (22 and 23) and tested their hydrolytic activity toward different diribonucleotides [45,46] (catalytic turnover was not demonstrated). The dimer and trimer structures of the active species were confirmed by measuring the hydrolytic activity as a function of Zn/L ratio, which show sharp maxima at the expected 2/1 and 3/1 ratios, respectively. The oligomer complexes have high ribonuclease activity (e.g. the hydrolysis of UpU is accelerated more than 4 and 5 orders of magnitude by 22 and 23, respectively), whereas the effect of the monomer complex 24 was not... 

The isolation of RNA is less straightforward than DNA. The sample is easily contaminated by ribonuclease causing breakdown of the RNA. Endogenous ribonuclease activity is prevented by addition of inhibitors in the early stages... 

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... 

Walters and Loring (88) have purified a 3 -nucleotidase about 50-fold from mung bean sprouts (Phaseolus aureus Roxb.). The enzyme hydrolyzes 3 -AMP, 3 -GMP, 3 -CMP in decreasing order and also hydrolyzes the 3 -phosphate group of coenzyme A. (89), but it has no significant activity for 2 - or 5 -ribonucleotides. For 3 -GMP, 3 -AMP, 3 -UMP, and 3 -CMP, Km values are 0.67, 1.1, 7.7, and 15 mM, respectively. The enzyme preparation also contained acid stable ribonuclease activity (89). Both 3 -nucleotidase and acid ribonuclease were inactivated reversibly at pH 5.0 and by dialysis and this inactivation could be prevented by Zn2+. The two activities were similarly inactivated by heat at pH 5 and 7.5. Such data indicate that the two are metalloproteins— probably zinc metalloproteins. These similarities and other kinetic data provide evidence that the 3 -nucleotidase and ribonuclease activities reside in the same protein. 

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). 

A wide variety of procedures have been used for assaying ribonuclease activity. Some measure only step 1 or step 2, some measure both, some use high molecular weight substrates, some low, some substrates are... 

K5. Kedra, B., Popiela, T., and Naskalski, J., Poly-C ribonuclease in acute pancreatitis. Part 1. Is blood serum poly-C ribonuclease activity an efficient necrosis indicator in acute pancreatitis [in Polish], Pol. Przegl. Chir. 66, 1237-1243 (1994). 

Nl. Naskalski, J. W., Determination of ribonuclease activity in serum of patients with pancreatic necrosis. Lab. Diag. 30,425—430 (1989). 

Truelsen, T. A. Indoleacetic acid-induced decrease of the ribonuclease activity in vivo. Physiol. Plant, 1967, 20, 1112-1119. 

Because derivatization impaired proteolysis, its effect on endogenous ribonclease was studied. Ribonuclease activity was inhibited with increasing succinylation and dropped sharply at an anhydride to protein ratio of 0.8 where 80% of e-NH2 groups of the total protein were succinylated (Fig. 5). Because the ribonuclease was inactivated, an increased nucleic acid content in the precipitated proteins was expected. However, we observed less nucleic acid (NA) in precipitated succinylated protein than in the non-modified controls. Maximum precipitation of succinylated protein occurred around pH 4.5 and contained only 1.8% nucleic acid on a... 

Figure 5. The effects of succinylation during extraction of yeast protein on the endogenous ribonuclease activity (pH 6.0, 55°C)...

Essential degradation. Reverse transcriptase has ribonuclease activity as well as polymerase activity. What is the role of its ribonuclease activity ... 

Al. Abdullah, F., and Pennington, R. J., Ribonuclease activity in normal and dystrophic human muscle. Clin. Chim. Acta 20, 365-371 (1968). 

PI, Prabhavathi, P, Mohanram, M., and Reddy, V., Ribonuclease activity in plasma and leukocytes of malnourished children. Clin, Chim. Acta 79, 591-593 (1977). 

Probst J, Brechtel S, Scheel B, et al. (2006). Characterization of the ribonuclease activity on the skin surface. Genet. Vaccines. Ther. 4 4. 

In the barnase-barstar system, there is a selective pressure on the kinetics of association, the ribonuclease activity being lethal if expressed in the cell. The genes form an operon and, when both proteins are produced together in the bacterium, barnase must be either excreted or immediately inhibited by barstar. Unlike the selection for tight binding, which operates almost exclusively on residues at the interface, the selection for fast binding acts on all charged residues of the two proteins. 

Tannins are naturally occurring water-soluble polyphenolic compoimds, and it has been reported that they show their anti-HIV activity by inhibiting polymerase and ribonuclease activities of HIV-1 RT. Phlorotannins are tannin derivatives which contain several phloroglucinol imits linked to each other in different ways and formed by the polymerization of phloroglucinol (1,3,5-trihydroxybenzene) monomer units and biosynthesis through the acetate-malonate pathway. So far, phlorotannins mostly have been isolated from red and brown alga. Numerous bioactivities of phlorotannins have been reported up to date such as antioxidant, antiinflammatory, antibacterial, and anti-MMP activities (Kim et al., 2006 Nagayama et al., 2002). 

Oost, T. Filippazzi. A. Kalesse. M. BA(guanidinium) receptors as ribonuclease active-site model systems Strac-tural changes and solvent effects. Liebigs Ann. 1997, 1005-1011. 

Ellis GA, McGrath NA, Palte MJ, Raines RT (2012) Ribonuclease-activated cancer prodrag. ACS Med Chem Lett 3 268-272... 

It is very important to ensure that all equipment and solutions used are treated to remove ribonuclease activity and that gloves are worn at all times to prevent contamination with ribonucleases present in... 

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