Luis Federico Leloir ForMemRS[1][2] (September 6, 1906 – December 2, 1987)[3] was an Argentine physician and biochemist who received the 1970 Nobel Prize in Chemistry for his discovery of the metabolic pathways by which carbohydrates are synthesized and converted into energy in the body.

[3] Although born in France, Leloir received the majority of his education at the University of Buenos Aires and was director of the private research group Fundación Instituto Campomar until his death in 1987.

His research into sugar nucleotides, carbohydrate metabolism, and renal hypertension garnered international attention and led to significant progress in understanding, diagnosing and treating the congenital disease galactosemia.

After being served prawns with the usual sauce during lunch with a group of friends at the Ocean Club in Mar del Plata, Leloir came up with a peculiar combination of ketchup and mayonnaise to spice up his meal.

The two would develop a close relationship, collaborating on various projects until Houssay's death in 1971; in his lecture after winning the Nobel Prize, Leloir claimed that his "whole research career has been influenced by one person, Prof. Bernardo A.

In 1936 he traveled to England to begin advanced studies at the University of Cambridge, under the supervision of another Nobel Prize winner, Sir Frederick Gowland Hopkins, who had obtained that distinction in 1929 for his work in physiology and in revealing the critical role of vitamins in maintaining good health.

However, his return to Argentina was amidst conflict and strife; Houssay had been expelled from the University of Buenos Aires[10] for signing a public petition opposing the Nazi regime in Germany and the military government led by Pedro Pablo Ramírez.

[12] During the final years of the 1940s, although lacking financial resources and operating with very low-cost teams, Leloir's successful experiments would reveal the chemical origins of sugar synthesis in yeast as well as the oxidation of fatty acids in the liver; together with J. M. Muñoz, he produced an active cell-free system, a first in scientific research.

[13] Along the way, Muñoz and Leloir, unable to procure the costly refrigerated centrifuge needed to separate cell contents, improvised by spinning a tire stuffed with salt and ice.

[12] By 1947 he had formed a team that included Ranwel Caputto, Enrico Cabib, Raúl Trucco, Alejandro Paladini, Carlos Cardini and José Luis Reissig, with whom he investigated and discovered why a malfunctioning kidney and angiotensin helped cause hypertension.

The institute would help develop scientific programs in budding Argentine universities as well as attract researchers and scholars from the United States, Japan, England, France, Spain, and other Latin American countries.

[8] Every morning his wife Amelia would drive him in their Fiat 600 and drop him off at 1719 Julián Alvarez Street, location of Fundación Instituto Campomar, with Leloir wearing the same worn out, gray overalls.

He worked sitting on the same straw seat for decades and encouraged colleagues to eat lunch in the laboratory to save time, bringing enough meat stew to share with everyone.