# Which mutated enzymes act as better drugs than their non-mutated form?

Is there an enzyme which is used as a drug (let it be called version $A$) and a mutated version of it ($M$), where the activity of $M$ was found to be higher than $A$?

Any references on such a case would be greatly acknowledged.

• A possible option: "Site-saturation mutagenesis of Tyr-105 reveals its importance in substrate stabilization and discrimination in TEM-1 β-lactamase" Feb 28, 2013 at 11:45
• Another option: "Most Efficient Cocaine Hydrolase Designed by Virtual Screening of Transition States" Mar 4, 2013 at 15:00
• A third option: "Why Does the G117H Mutation Considerably Improve the Activity of Human Butyrylcholinesterase against Sarin? Insights from Quantum Mechanical/Molecular Mechanical Free Energy Calculations" Mar 4, 2013 at 15:00
• Design of High-Activity Mutants of Human Butyrylcholinesterase against (−)-Cocaine: Structural and Energetic Factors Affecting the Catalytic Efficiency Mar 4, 2013 at 20:17

## 1 Answer

There are mutants of clotting factor VIII that have longer half lives and better activity than natural Factor VIII. Factor VIII is one of the missing proteins commonly involved in hemophilia. Hemophiliacs usually use injections of Factor VIII to prevent bleeding. The mutant form should last longer in the blood, with better activity, resulting in fewer injections.

Since this is a 2007 patent, I don't know if this product is actually being used to treat patients, drug approval takes a long time.