A Nobel Prize medal awarded to chemist Hans Krebs in 1953 is up for auction at Sotheby's London.
The lot is valued at ?�250,000-350,000 ($392,916-550,082).
Krebs received the medal for his discovery of the citric acid cycle, the process whereby food is converted into energy within a cell.
This finding has proven key in developing our understanding of life on Earth.
The lot is the latest in a series of high profile sales of Nobel Prize medals, with one example awarded to physicist Leon Lederman selling for $760,000 at Nate D Sanders earlier this year.
The record for a Nobel Prize stands at $4.7m, set in 2014 for the specimen awarded to DNA scientist James Watson.
A three-volume copy of JM Dent & Co's edition of Sir Thomas Malory's Le Morte d'Arthur is expected to make ?�25,000-30,000 ($38,443-46,131).
The lot is the rare first edition published in 1893-1894 that includes 19 of Aubrey Beardsley's original illustrations.
First published in 1485, the book brings together the various Arthurian legends into a single unified work.
Beardsley was an unknown when he was asked to provide the illustrations for the new edition. His style proved hugely influential in the development of art nouveau.
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