Riboflavin
The history of riboflavin, or vitamin B2, is an especially colorful one. It begins in 1879, when a water-soluble pigment was first discovered in milk. The pigment, which possessed a distinctive yellow-green fluorescence, was generally called lactoflavin-- lacto, for the milk, flavin, for the yellow coloring. But for several decades, no one really had a clue to the purpose of this oddly glowing substance.
Then, in the 1930s, a chemist named Otto Warburg —who was doing research on how damaged cells manage to repair themselves--isolated a substance from yeast that also had a yellowish glow. Warburg termed it the "yellow enzyme" and--because it appeared to play a role in cellular repair--subjected it to intense study. Before long, Warburg and his coworkers learned that the so-called yellow enzyme actually consisted of two factors: a protein factor and a nonprotein one, in this case a pigment. Somehow, both factors appeared necessary for the enzyme to perform its cell repairing function.
At roughly the same time, two other chemists, Richard Kuhn in Heidelberg, Germany, and Paul Karrer (1889-1971) in Zurich, Switzerland, were working independently with their research teams to better understand the recently discovered water-soluble vitamins, particularly those in the B family. Using somewhat different research methods, both scientists were able to isolate and crystallize vitamin B2, which, they quickly realized, was identical to lactoflavin. (Lactoflavin was now more often called riboflavin because it had been found to contain the sugar, ribose.) In 1935, Kuhn and Karrer were both able to synthesize the vitamin.
Kuhn and Karrer announced their discoveries at approximately the same time. Both prominent chemists were awarded the Nobel Prize in chemistry for their work with vitamins, Karrer in 1937 and Kuhn in 1938. (Because Adolph Hitler [1889-1945] refused to allow Germans to accept the Nobel Prize, Kuhn had to wait until after World War II ended before he could be honored for his work.) In his Nobel lecture, Karrer noted that vitamins, such as B2, were often part of enzymes and essential to effective biological action. He explained, as well, that Warburg's "yellow enzyme" was actually vitamin B2 combined with phosphoric acids.
Today, riboflavin (vitamin B2) is known to function as part of several enzyme systems, most of them concerned with cellular respiration and the oxidation of amino acids. Symptoms of a riboflavin deficiency include reddening of the lips, cracks in the corners of the mouth, as well as inflammation of the tongue and skin. In the early 1990's, such deficiencies were reported in Cuba as a result of the U.S. trade embargo. Between 1989 and 1995 the daily caloric intake for the citizens of this country went down a third, and serious problems with malnutrition, low birth weights, and vitamin deficiencies occurred as a result.
This is the complete article, containing 453 words
(approx. 2 pages at 300 words per page).
