title: Xanthomonas maltophilia CBS 897.97 as a source of new 7beta- and 7alpha-hydroxysteroid dehydrogenases and cholylglycine hydrolase: improved biotransformations of bile acids.
abstract: The paper reports the partial purification and characterization of the 7beta- and 7alpha-hydroxysteroid dehydrogenases (HSDH) and cholylglycine hydrolase (CGH), isolated from Xanthomonas maltophilia CBS 897.97. The activity of 7beta-HSDH and 7alpha-HSDH in the reduction of the 7-keto bile acids is determined. The affinity of 7beta-HSDH for bile acids is confirmed by the reduction, on analytical scale, to the corresponding 7beta-OH derivatives. A crude mixture of 7alpha- and 7beta-HSDH, in soluble or immobilized form, is employed in the synthesis, on preparative scale, of ursocholic and ursodeoxycholic acids starting from the corresponding 7alpha-derivatives. On the other hand, a partially purified 7beta-HSDH in a double enzyme system, where the couple formate/formate dehydrogenase allows the cofactor recycle, affords 6alpha-fluoro-3alpha, 7beta-dihydroxy-5beta-cholan-24-oic acid (6-FUDCA) by reduction of the corresponding 7-keto derivative. This compound is not obtainable by microbiological route. The efficient and mild hydrolysis of glycinates and taurinates of bile acids with CGH is also reported. Very promising results are also obtained with bile acid containing raw materials.
authors.affiliation: Dipartimento delle Risorse naturali e culturali, Università di Ferrara, C.so Ercole I d'Este 32, I-44100 Ferrara, Italy. pdp@unife.it
authors.forename: Paola
authors.initials: P
authors.lastname: Pedrini
authors.forename: Elisa
authors.initials: E
authors.lastname: Andreotti
authors.forename: Alessandra
authors.initials: A
authors.lastname: Guerrini
authors.forename: Mariangela
authors.initials: M
authors.lastname: Dean
authors.forename: Giancarlo
authors.initials: G
authors.lastname: Fantin
authors.forename: Pier Paolo
authors.initials: PP
authors.lastname: Giovannini
mesh_terms: D000581:Amidohydrolases / Q000302:isolation & purification / Q000378:metabolism*; D001647:Bile Acids and Salts / Q000378:metabolism*; D001711:Biotransformation; D003840:Deoxycholic Acid / Q000031:analogs & derivatives / Q000378:metabolism; D005998:Glycine / Q000737:chemistry; D006913:Hydroxysteroid Dehydrogenases / Q000302:isolation & purification / Q000378:metabolism*; D020615:Stenotrophomonas maltophilia / Q000201:enzymology*; D013654:Taurine / Q000737:chemistry; D014580:Ursodeoxycholic Acid / Q000031:analogs & derivatives / Q000378:metabolism
chemical_list: C092780:6-fluoro-ursodeoxycholic acid; D001647:Bile Acids and Salts; D003840:Deoxycholic Acid; D013654:Taurine; D014580:Ursodeoxycholic Acid; D006913:Hydroxysteroid Dehydrogenases; C031932:7 beta-hydroxysteroid dehydrogenase; C025376:7 alpha-hydroxysteroid dehydrogenase; D000581:Amidohydrolases; C023154:choloylglycine hydrolase; D005998:Glycine