Genomic DNA isolation Worthington ribonuclease A

Pancreatic ribonuclease  (RNase)  It is an endonuclease . It catalyzes nucleotide  5'- Ribose and adjacent pyrimidine nucleotides  3'- Cleavage of the phosphodiester bond between ribose linked phosphate groups . This cutting forms  2',3'- Cyclic phosphate , Then hydrolyze to the corresponding  3'- Nucleoside phosphate .

RNase  The content is the highest in the pancreas of ruminants （Barnard 1969）. The main component of crystallizing enzyme is  RNase A; A secondary component is  RNase B.RNase B  yes  RNase A  Glycosylation form of （Beintema et al. 1976）.

AI Meijie Worthington  Ribonuclease A Specificity ：

RNase A  It has specificity for pyrimidine nucleoside bond （Volkin  and  Cohn 1953）. The reaction is believed to take place in two steps . In step ,3',5'- The phosphate diester bond is cleaved , Simultaneous generation  2',3'- Cyclic diester phosphate intermediate . The second step , The cyclic phosphate diester is hydrolyzed to 3'- Monophosphate Group . Step is nonspecific for the nitrogenous base of the substrate ; However , The second step for the end is  2',3'- Pyrimidine nucleotides of cyclic phosphate are specific .RNase B  P-cyclic cytidine acid and yeast  RNA  Have and  RNase A  The same specificity （Plummer  and  Hirs 1963）.RNase A  Shows a preference for larger substrates （Nogués etc. , 1995）.

The cleavage rate of the enzyme at cytidine residue is twice that at uridine residue （Richards  and  Wyckoff 1971）. It has been found that  Thr45  It is most important to mediate pyrimidine specificity by forming hydrogen bonds with pyrimidine bases and spatially excluding purine base pairs （del Cardayré  and  Raines 1994）.Asp83  The side chain of is important to stabilize the transition state during the cleavage of uridine containing substrates ; The residue has no effect on the kinetics of cytidine cleavage （del Cardayré  and  Raines 1995）.

  

AI Meijie Worthington  Ribonuclease A Of 7 Applications ：

1.DNA In the process of separation RNA Remove

2.RNA Sequence analysis

3.RNase  Protection test

4.RNA Quantitative or mapping

5. Purified plasmid  DNA

6. Genome  DNA  Separate

7. Molecular weight marker

AI Meijie Worthington Ribonuclease A reference ：

1.Admed, A., Schaffer, S., and Wetlaufer, D.: Nonenzymic Reactivation of Reduced Bovine Pancreatic Ribonuclease by Air Oxidation and by Glutathione Oxidoreduction Buffers , J Biol Chem 250, 8477, 1975

2.Ahmad, F.: Free Energy Changes in Denaturation of Ribonuclease A by Mixed Denaturants. Effects of Combinations of Guanidine Hydrochloride and One of the Denaturants Lithium Bromide, Lithium Chloride and Sodium Bromide , J Biol Chem 259, 4183, 1984

 

3.Ahmad, F.: Free Energy Changes in Ribonuclease A Denaturation. Effect of Urea, Guanidine Hydrocholoride and Lithium Salt, J Biol Chem 258, 11143, 1983

Worthington Core enzyme ： Include ： Collagenase , Deoxyribonuclease I, Elastase , Papain , Ribonuclease , Trypsin, etc .