Biotin Antimetabolites
Many compounds more or less chemically related to biotin are known to inhibit the growthpromoting effect of biotin on various microorganisms. Each of a series of biotin homologues (various lengths of the side chain) was found to be capable of inhibiting the growth of Lactobacillus casei and Saccharomyces cerevisiae in the presence of biotin. It was pointed out that in this series of compounds the antibiotin activity was similar to the avidin-combining power. The mode of action of antimetabolites in general is not clear. However, important observations in this field have been reported.
It is well established that the fermentation rate of biotin-deficient yeast is markedly increased upon the addition of biotin to the medium. These authors showed that if certain biotin analogues (oxybiotinsulfonic acid and others) were added prior to the addition of biotin, the stimulatory effect of biotin was lost. However, if biotin had established the increased rate of fermentation, then the addition of the antimetabolites did not directly inhibit fermentation. From this it appears that the inhibitors act by preventing biotin from incorporating into a required coenzyme and not by inhibiting the action of the coenzyme in fermentation processes.
