Partial purification and properties of D-desthiobiotin synthetase from Escherichia coli.

ABSTRACT

d-Desthiobiotin synthetase, an enzyme that catalyzes the synthesis of d-desthiobiotin from dl-7,8-diaminopelargonic acid and HCO(3) (-), was purified 100-fold from cells of a biotin mutant strain of Escherichia coli. Adenosine triphosphate and Mg(2+) were shown, especially in purified extracts, to be obligatory for enzyme activity, although concentrations higher than 5 mm caused severe inhibition of the reaction with unpurified cell-free extracts. Adenosine diphosphate and adenosine monophosphate were shown to inhibit the reaction, but fluoride (up to 50 mm) had no detectable effect. The product of the enzyme reaction was identical to d-desthiobiotin on the basis of biological activity and chromatography. Furthermore, when H(14)CO(3) (-) was used as a substrate, the radioactive product was shown to be (14)C-desthiobiotin labeled exclusively in the ureido carbon.