Thomas Burr Osborne (chemist)

Thomas Burr Osborne (August 5, 1859 – January 29, 1929) was a biochemist and early discoverer of Vitamin A. He is known for his work isolating and characterizing seed proteins, and for determining protein nutritional requirements. His career was spent at the Connecticut Agricultural Experiment Station.

Thomas was the son of lawyer Arthur Dimon Osborne and the grandson of US Representative Thomas Burr Osborne.

His life exhibited "a single purpose, the understanding of the relationships of proteins to each other and the animal world. He began his researches upon vegetable proteins in 1888,..." He published his findings in The Vegetable Proteins in 1909.

Osborne wrote over 100 papers with longtime collaborator Lafayette Mendel. Both were appointees of the Connecticut Agricultural Experiment Station. In their early work, they studied the deadly poison ricin which is classified as a type 2 ribosome inactivating protein (RIP) from castor beans.

In 1909, Osborne and Mendel's work found what amino acids are necessary for the survival of the laboratory rat. At the Connecticut experimental station they developed a lab with about 200 rats whose dietary intake was carefully controlled. Their carefully controlled studies on rats revealed the necessary elements in a healthy diet. The program was described by J.R. Lindsey and H.J. Baker:

The striking differences in amino acid composition of plant proteins, which had been documented by Osborne, suggested that possible differences might exist in their biological value. The nutritive values of various purified proteins from cereal grains and other plant sources were compared for growth and maintenance in rats. This led to supplementation of "incomplete proteins" with those amino acids limiting each foodstuff’s "biological quality" (e.g. Tryptophan and lysine). Casein was found to be a "complete protein", thus paving the way for the use of this protein in modern rat diets. Within a few years it was possible to list the "essential" and "nonessential" amino acids.

The science of nutrition thus evolved beyond the caloric energy of food, turning to the structural issue of essential amino acids.

Vitamin A discovery

Osborne and Mendel discovered Vitamin A in 1913 in butter fat – independently discovered by Elmer McCollum and Marguerite Davis, who submitted their publication first, with both papers appearing in the same issue of the Journal of Biological Chemistry – as well as water-soluble vitamin B in milk. Osborne and Mendel showed, for example, that a lack of Vitamin A in the diet led to xerophthalmia. They also established the importance of lysine and tryptophan in a healthy diet.