American scientist Frances Arnold, who won the Nobel Prize for chemistry, has retracted her latest paper.
Prof Arnold shared the award with George P Smith and Gregory Winter for their research on enzymes in 2018.
A subsequent paper on enzymatic synthesis of beta-lactams was published in the journal Science in May 2019.
It has been retracted because the results were not reproducible, and the authors found data missing from a lab notebook.
Reproduction is an essential part of validating scientific experiments. If an experiment is a success, one would expect to get the same results every time it was conducted.
Prof Arnold came forward with the news herself on Twitter on 2 January.
"For my first work-related tweet of 2020, I am totally bummed to announce that we have retracted last year's paper on enzymatic synthesis of beta-lactams. The work has not been reproducible," she tweeted.
"It is painful to admit, but important to do so. I apologize to all. I was a bit busy when this was submitted, and did not do my job well."