Site-directed mutagenesis of bovine pancreatic ribonuclease: lysine-41 and aspartate-121.
Chemical modification studies suggest that two residues of bovine pancreatic ribonuclease A (RNase A), Lys-41 and Asp-121, are important for catalysis. Three mutants of RNase A have been prepared, two point mutants with Lys-41 altered to Arg-41 and Asp-121 altered to Glu-121, and a double mutant where both residues are altered. The Lys-41 Arg mutant has ca. 2% the catalytic activity (kcat/Km) of the native protein, while the Asp-121Glu mutant has ca. 17% the catalytic activity of the native protein. The double mutant has catalytic activity comparable to the Lys-41Arg mutant.
Trautwein
K
K
Laboratory for Organic Chemistry, E.T.H. Zürich, Switzerland.
Holliger
P
P
Stackhouse
J
J
Benner
S A
SA
D000595:Amino Acid Sequence; D000818:Animals; D001224:Aspartic Acid; D002417:Cattle; D005813:Genes, Synthetic; D008239:Lysine; D016297:Mutagenesis, Site-Directed; D012259:Ribonuclease, Pancreatic / Q000235:genetics* / Q000378:metabolism
D001224:Aspartic Acid; D012259:Ribonuclease, Pancreatic; D008239:Lysine