RNA hydrolysis

FIGURE 11.32 All example of nuclease specificity The specificity of RNA hydrolysis by bovine pancreatic RNase. This RNase cleaves h at 3 -pyriinidines, yielding oligonncleoddes with pyrimidine 3 -P04 ends. 

A number of less elaborate but, nevertheless, quite interesting systems have also been reported where just simple amino acids play a relevant role. Among them is an intriguing report by Komiyama s group [54] in which they describe RNA hydrolysis achieved as a result of the cooperation between carboxylate and ammonium ions. They prepared conjugates of glycine (or iminodiacetate) with an-... 

The above complexes have been shown to mimic the second step of RNA hydrolysis as well, i.e. the-efficient cleavage of ribonucleoside 2, 3 -cyclic monophosphates [55] with bell-shaped pH-rate profile. With these substrates 37 showed much higher bimetallic cooperativity the dime/2 m0nomer ratios range between 64 and 457 for the different 2, 3 -NMPs used, while for 38 this ratio varies between 1 and 26. Since the mononuclear complexes have nearly the same activity toward the different 2, 3 -NMPs, these kinetic data indicate a notable base-selectivity of the dimer complexes. Since no correlation was observed with the size,... 

RNA hydrolysis, 45 285-287, 297-299 metalloenzymes, 45 251-252 bleomycin, 45 252-260, 299 nucleic acid hydrolysis metal ions and, 45 283-285 by oligonucleotide modified with metal complexes, 45 297-299 of phosphodiesters, 45 251, 287-297 by ribozymes, 45 285-287 cleavage by iron bleomycin, 43 140 polymerase, arsonomethyl phosphonate analogue, 44 201-202 substructures, 43 133-134 transfer... 

A recent discovery in biochemistry is that RNA can act as an enzyme in chemical reactions, usually reactions involving RNA hydrolysis. Discuss the features of RNA structure that might favor evolution of enzymes composed entirely of a single polyribonucleotide chain, and describe a proposed mechanism for RNA-catalyzed hydrolysis of RNA molecules. 

Endogeneous and exogeneous ribonucleases have been used also to reduce NA under mild conditions (68). However, extensive proteolysis during incubation for RNA hydrolysis and the cost of the enzymes present sizable drawbacks (68,87). 

Thus, succinylation prevented the aggregation and coagulation of yeast proteins normally observed during RNA hydrolysis with endogenous ribonuclease and markedly increased the recovery of intact, soluble protein. Lindbloom (69) reported that up to 70% of yeast protein may be degraded during incubation to reduce RNA (pH 6,... 

Guanidines have been implemented early as recognition elements, guided by the apparent function of arginine in protein structures. The C2-symmetric, chiral anion receptor 52 was introduced by Lehn, Schmidtchen and de Mendoza consecutively and studied in various modifications (Scheme 13) [23c]. For example, an elaborate system based on 52 provided reasonable enantioselective recognition of amino acids [23c, 28]. Furthermore, bis(guanidinium) compounds catalyze RNA hydrolysis in the presence of external base via phosphodiester complexation [29]. The,se functional elements were joined in receptor 53 to yield a functional transesterification catalyst [30]. 

RNA hydrolysis mainly produces 2 -, 3 - and 5 -ribonucleotides. Although monophosphate nucleotides are well recognized in the food industry as flavour compounds (Charpentier et al. 2005), further studies are required to know their impact in the sensorial properties of sparkling wines. 

Effecting targeted, site-selective RNA hydrolysis is the other antisense-related area where the expanded porphyrins could prove advantageous. In point of fact, however, it is only the texaphyrins (of all the expanded porphyrin systems known)... 

Figure 10.4.4 Schematic Representation of the Lanthanide(IIl) Texaphyrin-based Approach to Antisense-type RNA Hydrolysis...

With trihydroxyethylenephosphorane (91) as a model for RNA hydrolysis, Karplus et al. developed a protocol for calculating the values of pKa and pKa of (91) based on estimates of the pKa for phosphoric acid. The protocol used density functional theory to calculate gas-phase protonation energies and continuum dielectric methods to determine solvation corrections and arrived at values of 7.9 and 14.3 for pKa and pKa respectively. These values are within the experimental ranges of 6.5-11.0 for pKa and 11.3-15.0 for pKa proposed for the molecules. 

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