title: Biotin synthase mechanism: on the origin of sulphur.
abstract: Biotin synthase catalyses the last step of the biosynthesis of biotin in microorganisms and plants. The active protein isolated from Bacillus sphaericus and Escherichia coli contains an iron-sulphur (FeS) cluster. The native enzymes were depleted of their iron and inorganic sulphide and the resulting apoenzymes were chemically reconstituted with FeCl3 and Na2[34S] to give labelled (Fe34S) enzymes. These enzymes were functional and when assayed in vitro produced labelled biotin containing about 65% of 34S. These data strongly support the hypothesis that the sulphur of biotin is derived from the (FeS) centre of the enzyme.
authors.affiliation: Laboratoire de Chimie Organique Biologique, Université Paris VI-CNRS UMR 7613, France.
authors.forename: B T
authors.initials: BT
authors.lastname: Bui
authors.forename: D
authors.initials: D
authors.lastname: Florentin
authors.forename: F
authors.initials: F
authors.lastname: Fournier
authors.forename: O
authors.initials: O
authors.lastname: Ploux
authors.forename: A
authors.initials: A
authors.lastname: Méjean
authors.forename: A
authors.initials: A
authors.lastname: Marquet
mesh_terms: D001051:Apoenzymes / Q000378:metabolism; D001407:Bacillus / Q000201:enzymology* / Q000378:metabolism; D001426:Bacterial Proteins / Q000378:metabolism; D001710:Biotin / Q000096:biosynthesis* / Q000737:chemistry; D002712:Chlorides; D004926:Escherichia coli / Q000201:enzymology* / Q000378:metabolism; D005290:Ferric Compounds / Q000378:metabolism; D020035:Holoenzymes / Q000378:metabolism; D007501:Iron / Q000378:metabolism; D007700:Kinetics; D013058:Mass Spectrometry; D008956:Models, Chemical; D013440:Sulfides / Q000378:metabolism; D013455:Sulfur / Q000378:metabolism*; D013466:Sulfurtransferases / Q000737:chemistry / Q000378:metabolism*
chemical_list: D001051:Apoenzymes; D001426:Bacterial Proteins; D002712:Chlorides; D005290:Ferric Compounds; D020035:Holoenzymes; D013440:Sulfides; D001710:Biotin; D013455:Sulfur; D007501:Iron; D013466:Sulfurtransferases; C057985:biotin synthetase; C024555:ferric chloride; C033479:sodium sulfide