Arnold became only the fifth woman to be awarded the prize.
While Arnold has won one half of the 9 million Swedish krona (Rs 7.3 crore) award, the other half would be shared by George Smith of University of Missouri in the United States and Gregory Winter of the MRC Laboratory of Molecular Biology in Britain.
Frances Arnold and George Smith of the US and Gregory Winter of the United Kingdom won the 2018 prize for work that showed scientists and drug developers how to force proteins to evolve.
Winter, who shared the prize with two other scientists for his work on the directed evolution of antibodies, says he realized afterward there was a "moral imperative" to ensure "what was produced could be used for public benefit". Because they are so useful, scientists had long tried to create enzymes with desired properties artificially, but with little success.
Winter said he was surprised by the huge commercial success of antibody drugs, which he put down in large part to the high prices that drug companies have managed to charge for them.
Sir Gregory Winter, 67, of Cambridge University, scooped the prestigious prize for pioneering methods which have led to the creation of a whole new class of drugs - now being used to treat breast cancer, multiple sclerosis and arthritis.
"All this tremendous beauty and complexity of the biological world all comes about through this one simple, lovely design algorithm", she said.
He built up a collection of phages, with billions of antibody varieties on their surface, and engineered them make them more effective. She looked into evolution. "But since I'm an engineer and not a gentleman, I had no problem with that", Arnold said in an interview in 2014. "To me it is obvious that this is the way it should be done". She wanted it to accelerate change in an organic solvent, so she created random mutations in the enzyme's genetic code and introduced the mutated genes to bacteria that then created different types of subtilisin. And then you could screen those to pick the best one for whatever objective you had.
"I am delighted that his great achievement has been recognised with the Nobel". And now I'm directly benefiting from the work that was honored today.
GREENFIELDBOYCE: So half of the award went to Frances Arnold.
Arnold graduated from the University in 1979 with a bachelor of science in engineering degree in mechanical and aerospace engineering.
Arnold received her P.h.D. from the University of California, Berkeley.
Arnold flew back to California for a news conference at Caltech, which she called a "jewel of an institution" where she was always "pushed to do her best and do things other people couldn't do". She was named the university's director of the Donna and Benjamin M. Rosen Bioengineering Center in 2013.
"At first glance it may seem that the Chemistry Nobel has been "biologised" again".
"I am absolutely floored". "I can't wait to get home and tell my son".