Article
Methotrexate-resistant variants of human dihydrofolate reductase with substitutions of leucine 22. Kinetics, crystallography, and potential as selectable markers.
The Journal of biological chemistry - 10 Mar 1995
Lewis W S, Cody V, Galitsky N, Luft J R, Pangborn W, Chunduru S K, Spencer H T, Appleman J R, Blakley R L
Abstract excerpt
Although substitution of tyrosine, phenylalanine, tryptophan, or arginine for leucine 22 in human dihydrofolate reductase greatly slows hydride transfer, there is little loss in overall activity (kcat) at pH 7.65 (except for the arginine 22 variant), but Km for dihydrofolate and NADPH are increased significantly. The greatest effect, decreased binding of methotrexate to the enzyme-NADPH complex by 740- to...
Topics
- Amino Acid Sequence
- Binding Sites
- Crystallography, X-Ray
- Drug Resistance
- Enzyme Stability
- Genetic Variation
- Humans
- Hydrogen-Ion Concentration
- Kinetics
- Leucine