Biotin biosynthesis: Synthesis and biological evaluation of the putative intermediate thiols

Article abstract of DOI:10.1021/ja00059a006

Previous results led to the conclusion that the last step of biotin biosynthesis, the sulfur insertion into dethiobiotin, should involve a thiol as intermediate. The three possible thiols have been synthesized and their biological activity was evaluated: the primary thiol 10 labeled with [³⁵S] or [³⁴S] or with deuterium was transformed into biotin by resting cells of Bacillus sphaericus without loss of the label. Hence, it is a possible intermediate. Interestingly, growing cells transformed [³⁵S]- or 5-[²H₂]-labeled 10 into biotin with loss of the labels. 10 and one of the secondary thiols 5B also promote the growth of Escherichia coli C124, a biotin auxotroph, but again they lose their sulfur during their conversion to biotin. The growing cells experiments reveal a complex pathway which remains to be elucidated.