Article
Substitution of aspartic acid-217 of Citrobacter freundii cephalosporinase and properties of the mutant enzymes.
FEBS letters - 21 May 1990
Tsukamoto K, Kikura R, Ohno R, Sawai T
Abstract excerpt
On the assumption that Asp-217 of a Citrobacter freundii cephalosporinase forms a salt-bridge with the conserved Lys-67, Asp-217 was changed to glutamic acid, threonine or lysine. The mutant enzymes retained about the same level of activity as that of the wild-type enzyme, and the participation of Asp-217 in the salt-bridge was ruled out. However, the mutations resulted in an increase in hydrolytic activity...
Topics
- Aspartic Acid
- Cephalosporinase
- Citrobacter
- Escherichia coli
- Gene Expression Regulation, Bacterial
- Genes, Bacterial
- Glutamates
- Glutamic Acid
- Kinetics
- Lysine
- Mutation