Translations:Vitamin B12/81/en

Identification of the active compound

While working at the Bureau of Dairy Industry, U.S. Department of Agriculture, Mary Shaw Shorb was assigned work on the bacterial strain Lactobacillus lactis Dorner (LLD), which was used to make yogurt and other cultured dairy products. The culture medium for LLD required liver extract. Shorb knew that the same liver extract was used to treat pernicious anemia (her father-in-law had died from the disease), and concluded that LLD could be developed as an assay method to identify the active compound. While at the University of Maryland she received a small grant from Merck, and in collaboration with Karl Folkers from that company, developed the LLD assay. This identified "LLD factor" as essential for the bacteria's growth. Shorb, Folker and Alexander R. Todd, at the University of Cambridge, used the LLD assay to extract the anti-pernicious anemia factor from liver extracts, purify it, and name it vitamin B₁₂. In 1955, Todd helped elucidate the structure of the vitamin. The complete chemical structure of the molecule was determined by Dorothy Hodgkin based on crystallographic data and published in 1955 for which, and for other crystallographic analyses, she was awarded the Nobel Prize in Chemistry in 1964. Hodgkin went on to decipher the structure of insulin.