Biotin can be synthesized by the human colon flora. The question to which extent this production contributes to covering the host-organism’s requirements is, however, subject to discussion. In most foods of animal origin as well as in cereals, biotin prevails in the protein (= enzyme)-bound form as ε-N-biotinyl-l-lysine (= biocytin). Brewer’s yeast, liver, soya beans, and peanuts number among the biotin rich foods [1].
The chemical structure of biotin (hexahydro-2-oxo-1H-thieno [3,4-d] imidazol-4-valeric acid) is shown in Fig. 1. Of the eight stereoisomers, only d-(+)-biotin occurs naturally and is biologically active.
