PMID: 9284Sep 1, 1976

The role of lysine-41 in ribonuclease A studied by proton-magnetic-resonance spectroscopy of guanidinated ribonuclease A

European Journal of Biochemistry
L R Brown, J H Bradbury


Ribonuclease A has been guanidinated at the lysine residues and the nona-guanidinated and deca-guanidinated (fully substituted) products separated. In confirmation of an earlier report by Glick and Barnard (1970), it has been shown by chemical procedures that the former derivative is not reacted at lysine-41. Guanidination of lysine-41 to produce the fully substituted product causes loss of enzymic activity without any apparent change of conformation, as tested by conformational comparisons (using proton magnetic resonance spectroscopy) including (a) difference spectroscopy, evidence for the involvement of lysine-41 in a catalytic role in the enzyme. Dimethylation of lysine-41 of nona-guanidinated ribonuclease A produces sharp proton resonances which shifts as the dimethylamino group is titrated and allow the determination of an apparent pK of 8.8 for unsubstituted lysine-41.


May 1, 1975·European Journal of Biochemistry·L R Brown, J H Bradbury
Dec 31, 1973·Annals of the New York Academy of Sciences·G C Roberts, F W Benz
Aug 21, 1970·Biochimica Et Biophysica Acta·D M Glick, E A Barnard
Apr 14, 1967·Journal of Molecular Biology·J Goldstein
Jul 1, 1959·Biochimica Et Biophysica Acta·H B DIXON

Related Concepts

Hydrogen-Ion Concentration
Lysine Hydrochloride
In Vivo NMR Spectroscopy
Plasma Protein Binding Capacity
Protein Conformation
Alkaline Ribonuclease

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