Abstract
5-(2-Thienyl)-valeric acid (TVA) was found to inhibit the growth of Bacillus sphaericus. The inhibition was restored by the intermediates of biotin biosynthesis, dethiobiotin (DTB) and 7, 8-diaminopelargonic acid (DAPA), as well as biotin. However, the intermediates in earlier steps, 7-keto-8-aminopelargonic acid (KAPA) and pimelic acid, had no recovering effect. When Rhodotorula glutinis, which was also sensitive for TVA, was cultivated in a medium containing TVA, the amount of DTB and biotin in culture filtrate was decreased, while that of KAPA was increased. Enzymic investigation revealed that TVA inhibits the DAPA aminotransferase reaction which is responsible for DA-PA synthesis from KAPA, while no other enzyme reactions involved in DTB synthesis from pimelic acid were inhibited. TVA was also suggested to inhibit a certain site of biotin synthesis from DTB. Five other thienyl derivatives exhibited no action as biotin antagonists. TVA inhibited the growth of various microorganisms including bacteria yeasts, molds, and actinomycetes at a concentration of 100 or 500 μg per ml.
