Abstract
Dethiobiotin was the main portion of the conversion products of pimelic acid in Phycomyces blakesleeanus. It is suggested that pimelic acid participates in biotin biosynthesis. P. blakesleeanus has a high activity to convert pimelic acid to dethiobiotin rather than to convert dethiobiotin to biotin. A reason for this phenomenon is proposed. The presence of two sites of activity in the biotin pathway of P. blakesleeanus, which were controlled by repression with exogenous biotin, is suggested. It is found that the synthesis of dethiobiotin and biotin is notably controlled and that dethiobiotin is a normal intermediate in biotin biosynthesis.
