Thiamine: Vitamin B1

The formula for thiamine is C 12 H 18 N 4 OS. It is prepared synthetically as the chloride hydrochloride. This is a white crystalline compound readily soluble in water. Thiamine is a combination of a pyrimidine ring and a sulfur-containing thiazole ring. The structural formula of the chloride hydrochloride is as follows:

Apparently all sorts of protoplasm need thiamine. Some types of cells can synthesize it, others can not. Higher organisms generally require the intact thiamine molecule; on the other hand some lower organisms are able to synthesize thiamine provided they can obtain both parts of the molecule, pyrimidine and thiazole. Other organisms may require either the pyrimidine fraction or the thiazole fraction, but not both. Many bacteria require neither and can synthesize whatever thiamine they need.

Lack of thiamine in the diet produces beriberi, a paralytic disease of men rather common in Japan and in various other portions of the world. In birds, lack of thiamine produces polyneuritis, a disease similar to beriberi. In this disease the nerve fibers show degenerative changes.

Experimentally, it has been shown that a similar paralysis could be produced in chicks, cats, pigeons and rats. The effect is due to the fact that some species of fish contain in their tissues an enzyme, thiaminase, which destroys thiamine. Thiaminase is found not only in fish but also in clams. In addition to its effect on the nervous system, lack of thiamine may also cause retardation of growth. Thiamine is important for the utilization of carbohydrate. Combined with 2 phosphate groups as diphosphothiamine, it forms part of an enzyme system that acts on pyruvic acid, a keto acid of great importance in intermediary metabolism. When animals are deprived of thiamine, their tissues are unable to oxidize pyruvic acid. Thiamine is also important in the transmission of the nerve impulse. When isolated nerves are stimulated, they are believed to release thiamine to the surrounding solution.