rnase a การใช้

• CNPase's catalytic core consists of three RNase A.
• One such enzyme is Ribonuclease A ( RNase A ), a protein enzyme.
• RNase A cleaves specifically after pyrimidine nucleotides.
• The positive charges of RNase A lie mainly in a deep cleft between two lobes.
• RNase A is a relatively small protein ( 124 residues, ~ 13.7 kDa ).
• RNase A was the first enzyme for which a correct catalytic mechanism was proposed, even before its structure was known.
• Prior to or during the staining step, the cells are often treated with RNase A to remove RNAs from the cells.
• This generous act made RNase A the main protein for basic research for the next few decades, resulting in several Nobel Prizes.
• It is intriguing to ask whether the domestication of the ox is related to the emergence of seminal RNase as a functioning protein.
• A lysine residue, also in the active site of RNase A, stabilizes the negatively charged oxygen atoms in the transition state.
• RNase A was the first protein for showing the effects of non-native isomers of peptide bonds preceding proline residues in protein folding.
• RNase A has four disulfide bonds in its native state : Cys26-Cys84, Cys58-110, Cys40-95 and Cys65-72.
• TAT was able to deliver different proteins, such as horseradish peroxidase and RNase A across cell membrane into the cytoplasm in different cell lines " in vitro ".
• The N-terminal ?-helix of RNase A ( residues 3-13 ) is connected to the rest of RNase A by a flexible linker ( residues 16-23 ).
• The N-terminal ?-helix of RNase A ( residues 3-13 ) is connected to the rest of RNase A by a flexible linker ( residues 16-23 ).
• It remains commonly referred to as " ribonuclease A " or " RNase A " as the most prominent member of its protein family, known variously as pancreatic ribonuclease, ribonuclease A, or ribonuclease I.
• As RNase A cleaves RNA specifically at cytosine and uracil ribonucleotides, base-specificity is achieved by adding incorporating cleavage-resistant dTTP when cytosine-specific ( C-specific ) cleavage is desired, and incorporating dCTP when uracil-specific ( U-specific ) cleavage is desired.
• RNase A contains histidine in its active site, and uses it to accomplish acid-base catalysis and cleavage of RNA . Certain histidine residues in the active site act as bases to remove protons from 2 hydroxyls of ribose sugars, while others act as acids to donate protons to the 5 oxygen of adjacent riboses to make them better leaving groups.
• Another mechanism of protection is "'ribonuclease inhibitor ( RI ) "', which comprises a relatively large fraction of cellular protein ( ~ 0.1 % ) in some cell types, and which binds to certain ribonucleases with the highest affinity of any protein-protein interaction; the dissociation constant for the RI-RNase A complex is ~ 20 fM under physiological conditions.
• However, angiogenin is unique among the many proteins that are involved in angiogenesis in that it is also an enzyme with an amino acid sequence 33 % identical to that of bovine pancreatic ribonuclease ( RNase ) A . Although angiogenin contains many of the same catalytic residues as RNase A, it cleaves standard RNA substrates 10 5  10 6 times less efficiently than does RNase A . Removal of this residue through mutation increases the ribonuclease activity between 11 and 30 fold.