The Role of Lysine-7 in Ribonuclease-A

  • Bruno Filippi
  • Gianfranco Borin
  • Fernando Marchiori
Part of the Experimental Biology and Medicine book series (EBAM, volume 19)


Bovine pancreatic ribonuclease A(RNase A) catalyzes the hydrolysis of RNA by a two-stage mechanism. The first step is a transphosphorylation to give an oligonucleotide terminating in a pyrimidine 2′-3′-cyclic phosphate. The second is the hydrolysis of the cyclic phosphate to give a terminal 3′-phosphate. At present it is not clear whether the invariant lysine-7 plays any part in the enzyme activity. Chemical modifications of the ε-ammonium group give derivatives with 15–30% activity, but substrate binding has been observed to be unaffected. On the other hand, the X-ray crystallography data, while confirming that Lys-7 is located relatively close to and with free access to the active site, strongly suggest that this residue is still too far away from the site to interact with the substrate (1).


Circular Dichroism Ammonium Group Cyclic Phosphate Electronic Structure Theory Total Ionic Strength 
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Copyright information

© The Humana Press Inc. 1987

Authors and Affiliations

  • Bruno Filippi
    • 1
  • Gianfranco Borin
    • 1
  • Fernando Marchiori
    • 1
  1. 1.Department of Organic Chemistry, Biopolymer Research CenterUniversity of PaduaPaduaItaly

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